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a8b00268 |
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20-Nov-2023 |
Al Viro <viro@zeniv.linux.org.uk> |
rename(): avoid a deadlock in the case of parents having no common ancestor ... and fix the directory locking documentation and proof of correctness. Holding ->s_vfs_rename_mutex *almost* prevents ->d_parent changes; the case where we really don't want it is splicing the root of disconnected tree to somewhere. In other words, ->s_vfs_rename_mutex is sufficient to stabilize "X is an ancestor of Y" only if X and Y are already in the same tree. Otherwise it can go from false to true, and one can construct a deadlock on that. Make lock_two_directories() report an error in such case and update the callers of lock_rename()/lock_rename_child() to handle such errors. And yes, such conditions are not impossible to create ;-/ Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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b4fa966f |
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28-Jun-2023 |
David Howells <dhowells@redhat.com> |
mm, netfs, fscache: stop read optimisation when folio removed from pagecache Fscache has an optimisation by which reads from the cache are skipped until we know that (a) there's data there to be read and (b) that data isn't entirely covered by pages resident in the netfs pagecache. This is done with two flags manipulated by fscache_note_page_release(): if (... test_bit(FSCACHE_COOKIE_HAVE_DATA, &cookie->flags) && test_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags)) clear_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags); where the NO_DATA_TO_READ flag causes cachefiles_prepare_read() to indicate that netfslib should download from the server or clear the page instead. The fscache_note_page_release() function is intended to be called from ->releasepage() - but that only gets called if PG_private or PG_private_2 is set - and currently the former is at the discretion of the network filesystem and the latter is only set whilst a page is being written to the cache, so sometimes we miss clearing the optimisation. Fix this by following Willy's suggestion[1] and adding an address_space flag, AS_RELEASE_ALWAYS, that causes filemap_release_folio() to always call ->release_folio() if it's set, even if PG_private or PG_private_2 aren't set. Note that this would require folio_test_private() and page_has_private() to become more complicated. To avoid that, in the places[*] where these are used to conditionalise calls to filemap_release_folio() and try_to_release_page(), the tests are removed the those functions just jumped to unconditionally and the test is performed there. [*] There are some exceptions in vmscan.c where the check guards more than just a call to the releaser. I've added a function, folio_needs_release() to wrap all the checks for that. AS_RELEASE_ALWAYS should be set if a non-NULL cookie is obtained from fscache and cleared in ->evict_inode() before truncate_inode_pages_final() is called. Additionally, the FSCACHE_COOKIE_NO_DATA_TO_READ flag needs to be cleared and the optimisation cancelled if a cachefiles object already contains data when we open it. [dwysocha@redhat.com: call folio_mapping() inside folio_needs_release()] Link: https://github.com/DaveWysochanskiRH/kernel/commit/902c990e311120179fa5de99d68364b2947b79ec Link: https://lkml.kernel.org/r/20230628104852.3391651-3-dhowells@redhat.com Fixes: 1f67e6d0b188 ("fscache: Provide a function to note the release of a page") Fixes: 047487c947e8 ("cachefiles: Implement the I/O routines") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Dave Wysochanski <dwysocha@redhat.com> Reported-by: Rohith Surabattula <rohiths.msft@gmail.com> Suggested-by: Matthew Wilcox <willy@infradead.org> Tested-by: SeongJae Park <sj@kernel.org> Cc: Daire Byrne <daire.byrne@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Steve French <sfrench@samba.org> Cc: Shyam Prasad N <nspmangalore@gmail.com> Cc: Rohith Surabattula <rohiths.msft@gmail.com> Cc: Dave Wysochanski <dwysocha@redhat.com> Cc: Dominique Martinet <asmadeus@codewreck.org> Cc: Ilya Dryomov <idryomov@gmail.com> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jingbo Xu <jefflexu@linux.alibaba.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Xiubo Li <xiubli@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
cbb0b9d4 |
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15-Jun-2023 |
Amir Goldstein <amir73il@gmail.com> |
fs: use a helper for opening kernel internal files cachefiles uses kernel_open_tmpfile() to open kernel internal tmpfile without accounting for nr_files. cachefiles uses open_with_fake_path() for the same reason without the need for a fake path. Fork open_with_fake_path() to kernel_file_open() which only does the noaccount part and use it in cachefiles. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Message-Id: <20230615112229.2143178-3-amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
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d56e0ddb |
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15-Jun-2023 |
Amir Goldstein <amir73il@gmail.com> |
fs: rename {vfs,kernel}_tmpfile_open() Overlayfs and cachefiles use vfs_open_tmpfile() to open a tmpfile without accounting for nr_files. Rename this helper to kernel_tmpfile_open() to better reflect this helper is used for kernel internal users. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Message-Id: <20230615112229.2143178-2-amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
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79aa2849 |
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19-May-2023 |
David Howells <dhowells@redhat.com> |
cachefiles: Allow the cache to be non-root Set mode 0600 on files in the cache so that cachefilesd can run as an unprivileged user rather than leaving the files all with 0. Directories are already set to 0700. Userspace then needs to set the uid and gid before issuing the "bind" command and the cache must've been chown'd to those IDs. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> cc: David Howells <dhowells@redhat.com> cc: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com cc: linux-erofs@lists.ozlabs.org cc: linux-fsdevel@vger.kernel.org Message-Id: <1853230.1684516880@warthog.procyon.org.uk> Signed-off-by: Christian Brauner <brauner@kernel.org>
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#
abf08576 |
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12-Jan-2023 |
Christian Brauner <brauner@kernel.org> |
fs: port vfs_*() helpers to struct mnt_idmap Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
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24a81759 |
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23-Sep-2022 |
Miklos Szeredi <mszeredi@redhat.com> |
cachefiles: use vfs_tmpfile_open() helper Use the vfs_tmpfile_open() helper instead of doing tmpfile creation and opening separately. The only minor difference is that previously no permission checking was done, while vfs_tmpfile_open() will call may_open() with zero access mask (i.e. no access is checked). Even if this would make a difference with callers caps (don't see how it could, even in the LSM codepaths) cachfiles raises caps before performing the tmpfile creation, so this extra permission check will not result in any regression. Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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#
08d7a6fb |
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23-Sep-2022 |
Miklos Szeredi <mszeredi@redhat.com> |
cachefiles: only pass inode to *mark_inode_inuse() helpers The only reason to pass dentry was because of a pr_notice() text. Move that to the two callers where it makes sense and add a WARN_ON() to the third. file_inode(file) is never NULL on an opened file. Remove check in cachefiles_unmark_inode_in_use(). Do not open code cachefiles_do_unmark_inode_in_use() in cachefiles_put_directory(). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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38017d44 |
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23-Sep-2022 |
Miklos Szeredi <mszeredi@redhat.com> |
cachefiles: tmpfile error handling cleanup Separate the error labels from the success path and use 'ret' to store the error value before jumping to the error label. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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c8383054 |
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25-Apr-2022 |
Jeffle Xu <jefflexu@linux.alibaba.com> |
cachefiles: notify the user daemon when looking up cookie Fscache/CacheFiles used to serve as a local cache for a remote networking fs. A new on-demand read mode will be introduced for CacheFiles, which can boost the scenario where on-demand read semantics are needed, e.g. container image distribution. The essential difference between these two modes is seen when a cache miss occurs: In the original mode, the netfs will fetch the data from the remote server and then write it to the cache file; in on-demand read mode, fetching the data and writing it into the cache is delegated to a user daemon. As the first step, notify the user daemon when looking up cookie. In this case, an anonymous fd is sent to the user daemon, through which the user daemon can write the fetched data to the cache file. Since the user daemon may move the anonymous fd around, e.g. through dup(), an object ID uniquely identifying the cache file is also attached. Also add one advisory flag (FSCACHE_ADV_WANT_CACHE_SIZE) suggesting that the cache file size shall be retrieved at runtime. This helps the scenario where one cache file contains multiple netfs files, e.g. for the purpose of deduplication. In this case, netfs itself has no idea the size of the cache file, whilst the user daemon should give the hint on it. Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> Link: https://lore.kernel.org/r/20220509074028.74954-3-jefflexu@linux.alibaba.com Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
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ea5dc046 |
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30-Mar-2022 |
Jeffle Xu <jefflexu@linux.alibaba.com> |
cachefiles: unmark inode in use in error path Unmark inode in use if error encountered. If the in-use flag leakage occurs in cachefiles_open_file(), Cachefiles will complain "Inode already in use" when later another cookie with the same index key is looked up. If the in-use flag leakage occurs in cachefiles_create_tmpfile(), though the "Inode already in use" warning won't be triggered, fix the leakage anyway. Reported-by: Gao Xiang <hsiangkao@linux.alibaba.com> Fixes: 1f08c925e7a3 ("cachefiles: Implement backing file wrangling") Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: linux-cachefs@redhat.com Link: https://listman.redhat.com/archives/linux-cachefs/2022-March/006615.html # v1 Link: https://listman.redhat.com/archives/linux-cachefs/2022-March/006618.html # v2
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b64a3314 |
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14-Jan-2022 |
David Howells <dhowells@redhat.com> |
cachefiles: Trace active-mark failure Add a tracepoint to log failure to apply an active mark to a file in addition to tracing successfully setting and unsetting the mark. Also include the backing file inode number in the message logged to dmesg. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/164251404666.3435901.17331742792401482190.stgit@warthog.procyon.org.uk/ # v1
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8c39b8bc |
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14-Jan-2022 |
David Howells <dhowells@redhat.com> |
cachefiles: Make some tracepoint adjustments Make some adjustments to tracepoints to make the tracing a bit more followable: (1) Standardise on displaying the backing inode number as "B=<hex>" with no leading zeros. (2) Make the cachefiles_lookup tracepoint log the directory inode number as well as the looked-up inode number. (3) Add a cachefiles_lookup tracepoint into cachefiles_get_directory() to log directory lookup. (4) Add a new cachefiles_mkdir tracepoint and use that to log a successful mkdir from cachefiles_get_directory(). (5) Make the cachefiles_unlink and cachefiles_rename tracepoints log the inode number of the affected file/dir rather than dentry struct pointers. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/164251403694.3435901.9797725381831316715.stgit@warthog.procyon.org.uk/ # v1
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#
9f08ebc3 |
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22-Oct-2021 |
David Howells <dhowells@redhat.com> |
fscache, cachefiles: Display stat of culling events Add a stat counter of culling events whereby the cache backend culls a file to make space (when asked by cachefilesd in this case) and display in /proc/fs/fscache/stats. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819654165.215744.3797804661644212436.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906961387.143852.9291157239960289090.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967168266.1823006.14436200166581605746.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021567619.640689.4339228906248763197.stgit@warthog.procyon.org.uk/ # v4
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3929eca7 |
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21-Oct-2021 |
David Howells <dhowells@redhat.com> |
fscache, cachefiles: Display stats of no-space events Add stat counters of no-space events that caused caching not to happen and display in /proc/fs/fscache/stats. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819653216.215744.17210522251617386509.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906958369.143852.7257100711818401748.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967166917.1823006.14842444049198947892.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021566184.640689.4417328329632709265.stgit@warthog.procyon.org.uk/ # v4
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1f08c925 |
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21-Oct-2021 |
David Howells <dhowells@redhat.com> |
cachefiles: Implement backing file wrangling Implement the wrangling of backing files, including the following pieces: (1) Lookup and creation of a file on disk, using a tmpfile if the file isn't yet present. The file is then opened, sized for DIO and the file handle is attached to the cachefiles_object struct. The inode is marked to indicate that it's in use by a kernel service. (2) Invalidation of an object, creating a tmpfile and switching the file pointer in the cachefiles object. (3) Committing a file to disk, including setting the coherency xattr on it and, if necessary, creating a hard link to it. Note that this would be a good place to use Omar Sandoval's vfs_link() with AT_LINK_REPLACE[1] as I may have to unlink an old file before I can link a tmpfile into place. (4) Withdrawal of open objects when a cache is being withdrawn or a cookie is relinquished. This involves committing or discarding the file. Changes ======= ver #2: - Fix logging of wrong error[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/20211203094950.GA2480@kili/ [1] Link: https://lore.kernel.org/r/163819644097.215744.4505389616742411239.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906949512.143852.14222856795032602080.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967158526.1823006.17482695321424642675.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021557060.640689.16373541458119269871.stgit@warthog.procyon.org.uk/ # v4
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07a90e97 |
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21-Oct-2021 |
David Howells <dhowells@redhat.com> |
cachefiles: Implement culling daemon commands Implement the ability for the userspace daemon to try and cull a file or directory in the cache. Two daemon commands are implemented: (1) The "inuse" command. This queries if a file is in use or whether it can be deleted. It checks the S_KERNEL_FILE flag on the inode referred to by the specified filename. (2) The "cull" command. This asks for a file or directory to be removed, where removal means either unlinking it or moving it to the graveyard directory for userspace to dismantle. Changes ======= ver #2: - Fix logging of wrong error[1]. - Need to unmark an inode we've moved to the graveyard before unlocking. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/20211203094950.GA2480@kili/ [1] Link: https://lore.kernel.org/r/163819643179.215744.13641580295708315695.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906945705.143852.8177595531814485350.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967155792.1823006.1088936326902550910.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021555037.640689.9472627499842585255.stgit@warthog.procyon.org.uk/ # v4
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169379ea |
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18-Nov-2021 |
David Howells <dhowells@redhat.com> |
cachefiles: Mark a backing file in use with an inode flag Use an inode flag, S_KERNEL_FILE, to mark that a backing file is in use by the kernel to prevent cachefiles or other kernel services from interfering with that file. Using S_SWAPFILE instead isn't really viable as that has other effects in the I/O paths. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819642273.215744.6414248677118690672.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906943215.143852.16972351425323967014.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967154118.1823006.13227551961786743991.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021541207.640689.564689725898537127.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/164021552299.640689.10578652796777392062.stgit@warthog.procyon.org.uk/ # v4
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32759f7d |
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21-Oct-2021 |
David Howells <dhowells@redhat.com> |
cachefiles: Implement a function to get/create a directory in the cache Implement a function to get/create structural directories in the cache. This is used for setting up a cache and creating volume substructures. The directory in memory are marked with the S_KERNEL_FILE inode flag whilst they're in use to tell rmdir to reject attempts to remove them. Changes ======= ver #3: - Return an indication as to whether the directory was freshly created. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819631182.215744.3322471539523262619.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906933130.143852.962088616746509062.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967141952.1823006.7832985646370603833.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021542169.640689.18266858945694357839.stgit@warthog.procyon.org.uk/ # v4
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1bd9c4e4 |
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18-Nov-2021 |
David Howells <dhowells@redhat.com> |
vfs, cachefiles: Mark a backing file in use with an inode flag Use an inode flag, S_KERNEL_FILE, to mark that a backing file is in use by the kernel to prevent cachefiles or other kernel services from interfering with that file. Alter rmdir to reject attempts to remove a directory marked with this flag. This is used by cachefiles to prevent cachefilesd from removing them. Using S_SWAPFILE instead isn't really viable as that has other effects in the I/O paths. Changes ======= ver #3: - Check for the object pointer being NULL in the tracepoints rather than the caller. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819630256.215744.4815885535039369574.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906931596.143852.8642051223094013028.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967141000.1823006.12920680657559677789.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021541207.640689.564689725898537127.stgit@warthog.procyon.org.uk/ # v4
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850cba06 |
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30-Oct-2021 |
David Howells <dhowells@redhat.com> |
cachefiles: Delete the cachefiles driver pending rewrite Delete the code from the cachefiles driver to make it easier to rewrite and resubmit in a logical manner. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819577641.215744.12718114397770666596.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906883770.143852.4149714614981373410.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967076066.1823006.7175712134577687753.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021483619.640689.7586546280515844702.stgit@warthog.procyon.org.uk/ # v4
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8beabdde |
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19-Oct-2020 |
David Howells <dhowells@redhat.com> |
cachefiles: Change %p in format strings to something else Change plain %p in format strings in cachefiles code to something more useful, since %p is now hashed before printing and thus no longer matches the contents of an oops register dump. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/160588476042.3465195.6837847445880367183.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/162431200692.2908479.9253374494073633778.stgit@warthog.procyon.org.uk/
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6ae9bd8b |
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12-May-2021 |
David Howells <dhowells@redhat.com> |
fscache, cachefiles: Remove the histogram stuff Remove the histogram stuff as it's mostly going to be outdated. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/162431195953.2908479.16770977195634296638.stgit@warthog.procyon.org.uk/
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6521f891 |
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21-Jan-2021 |
Christian Brauner <christian.brauner@ubuntu.com> |
namei: prepare for idmapped mounts The various vfs_*() helpers are called by filesystems or by the vfs itself to perform core operations such as create, link, mkdir, mknod, rename, rmdir, tmpfile and unlink. Enable them to handle idmapped mounts. If the inode is accessed through an idmapped mount map it into the mount's user namespace and pass it down. Afterwards the checks and operations are identical to non-idmapped mounts. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-15-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
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9fe61450 |
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21-Jan-2021 |
Christian Brauner <christian.brauner@ubuntu.com> |
namei: introduce struct renamedata In order to handle idmapped mounts we will extend the vfs rename helper to take two new arguments in follow up patches. Since this operations already takes a bunch of arguments add a simple struct renamedata and make the current helper use it before we extend it. Link: https://lore.kernel.org/r/20210121131959.646623-14-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
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#
b4d0d230 |
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20-May-2019 |
Thomas Gleixner <tglx@linutronix.de> |
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public licence as published by the free software foundation either version 2 of the licence or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 114 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520170857.552531963@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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#
081d7d35 |
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14-May-2019 |
Sabyasachi Gupta <sabyasachi.linux@gmail.com> |
fs/cachefiles/namei.c: remove duplicate header linux/xattr.h is included more than once. Link: http://lkml.kernel.org/r/5c86803d.1c69fb81.1a7c6.2b78@mx.google.com Signed-off-by: Sabyasachi Gupta <sabyasachi.linux@gmail.com> Acked-by: Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
34e06fe4 |
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13-Jul-2018 |
Arnd Bergmann <arnd@arndb.de> |
cachefiles: avoid deprecated get_seconds() get_seconds() returns an unsigned long can overflow on some architectures and is deprecated because of that. In cachefs, we cast that number to a a 32-bit integer, which will overflow in year 2106 on all architectures. As confirmed by David Howells, the overflow probably isn't harmful in the end, since the timestamps are only used to make the file names unique, but they don't strictly have to be in monotonically increasing order since the files only exist in order to be deleted as quickly as possible. Moving to ktime_get_real_seconds() avoids the deprecated interface. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: David Howells <dhowells@redhat.com>
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#
b7e768b7 |
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24-Sep-2018 |
Nathan Chancellor <nathan@kernel.org> |
cachefiles: Explicitly cast enumerated type in put_object Clang warns when one enumerated type is implicitly converted to another. fs/cachefiles/namei.c:247:50: warning: implicit conversion from enumeration type 'enum cachefiles_obj_ref_trace' to different enumeration type 'enum fscache_obj_ref_trace' [-Wenum-conversion] cache->cache.ops->put_object(&xobject->fscache, cachefiles_obj_put_wait_retry); Silence this warning by explicitly casting to fscache_obj_ref_trace, which is also done in put_object. Reported-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com>
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#
169b8033 |
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17-Oct-2018 |
Al Viro <viro@zeniv.linux.org.uk> |
cachefiles: fix the race between cachefiles_bury_object() and rmdir(2) the victim might've been rmdir'ed just before the lock_rename(); unlike the normal callers, we do not look the source up after the parents are locked - we know it beforehand and just recheck that it's still the child of what used to be its parent. Unfortunately, the check is too weak - we don't spot a dead directory since its ->d_parent is unchanged, dentry is positive, etc. So we sail all the way to ->rename(), with hosting filesystems _not_ expecting to be asked renaming an rmdir'ed subdirectory. The fix is easy, fortunately - the lock on parent is sufficient for making IS_DEADDIR() on child safe. Cc: stable@vger.kernel.org Fixes: 9ae326a69004 (CacheFiles: A cache that backs onto a mounted filesystem) Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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#
b07581d2 |
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05-Oct-2018 |
Al Viro <viro@zeniv.linux.org.uk> |
cachefiles: fix the race between cachefiles_bury_object() and rmdir(2) the victim might've been rmdir'ed just before the lock_rename(); unlike the normal callers, we do not look the source up after the parents are locked - we know it beforehand and just recheck that it's still the child of what used to be its parent. Unfortunately, the check is too weak - we don't spot a dead directory since its ->d_parent is unchanged, dentry is positive, etc. So we sail all the way to ->rename(), with hosting filesystems _not_ expecting to be asked renaming an rmdir'ed subdirectory. The fix is easy, fortunately - the lock on parent is sufficient for making IS_DEADDIR() on child safe. Cc: stable@vger.kernel.org Fixes: 9ae326a69004 (CacheFiles: A cache that backs onto a mounted filesystem) Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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#
c2412ac4 |
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21-Jun-2018 |
Kiran Kumar Modukuri <kiran.modukuri@gmail.com> |
cachefiles: Wait rather than BUG'ing on "Unexpected object collision" If we meet a conflicting object that is marked FSCACHE_OBJECT_IS_LIVE in the active object tree, we have been emitting a BUG after logging information about it and the new object. Instead, we should wait for the CACHEFILES_OBJECT_ACTIVE flag to be cleared on the old object (or return an error). The ACTIVE flag should be cleared after it has been removed from the active object tree. A timeout of 60s is used in the wait, so we shouldn't be able to get stuck there. Fixes: 9ae326a69004 ("CacheFiles: A cache that backs onto a mounted filesystem") Signed-off-by: Kiran Kumar Modukuri <kiran.modukuri@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com>
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#
5ce83d4b |
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21-Jun-2018 |
Kiran Kumar Modukuri <kiran.modukuri@gmail.com> |
cachefiles: Fix missing clear of the CACHEFILES_OBJECT_ACTIVE flag In cachefiles_mark_object_active(), the new object is marked active and then we try to add it to the active object tree. If a conflicting object is already present, we want to wait for that to go away. After the wait, we go round again and try to re-mark the object as being active - but it's already marked active from the first time we went through and a BUG is issued. Fix this by clearing the CACHEFILES_OBJECT_ACTIVE flag before we try again. Analysis from Kiran Kumar Modukuri: [Impact] Oops during heavy NFS + FSCache + Cachefiles CacheFiles: Error: Overlong wait for old active object to go away. BUG: unable to handle kernel NULL pointer dereference at 0000000000000002 CacheFiles: Error: Object already active kernel BUG at fs/cachefiles/namei.c:163! [Cause] In a heavily loaded system with big files being read and truncated, an fscache object for a cookie is being dropped and a new object being looked. The new object being looked for has to wait for the old object to go away before the new object is moved to active state. [Fix] Clear the flag 'CACHEFILES_OBJECT_ACTIVE' for the new object when retrying the object lookup. [Testcase] Have run ~100 hours of NFS stress tests and have not seen this bug recur. [Regression Potential] - Limited to fscache/cachefiles. Fixes: 9ae326a69004 ("CacheFiles: A cache that backs onto a mounted filesystem") Signed-off-by: Kiran Kumar Modukuri <kiran.modukuri@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com>
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#
9c3e9025 |
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10-May-2018 |
Al Viro <viro@zeniv.linux.org.uk> |
cachefiles: vfs_mkdir() might succeed leaving dentry negative unhashed That can (and does, on some filesystems) happen - ->mkdir() (and thus vfs_mkdir()) can legitimately leave its argument negative and just unhash it, counting upon the lookup to pick the object we'd created next time we try to look at that name. Some vfs_mkdir() callers forget about that possibility... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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#
402cb8dd |
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04-Apr-2018 |
David Howells <dhowells@redhat.com> |
fscache: Attach the index key and aux data to the cookie Attach copies of the index key and auxiliary data to the fscache cookie so that: (1) The callbacks to the netfs for this stuff can be eliminated. This can simplify things in the cache as the information is still available, even after the cache has relinquished the cookie. (2) Simplifies the locking requirements of accessing the information as we don't have to worry about the netfs object going away on us. (3) The cache can do lazy updating of the coherency information on disk. As long as the cache is flushed before reboot/poweroff, there's no need to update the coherency info on disk every time it changes. (4) Cookies can be hashed or put in a tree as the index key is easily available. This allows: (a) Checks for duplicate cookies can be made at the top fscache layer rather than down in the bowels of the cache backend. (b) Caching can be added to a netfs object that has a cookie if the cache is brought online after the netfs object is allocated. A certain amount of space is made in the cookie for inline copies of the data, but if it won't fit there, extra memory will be allocated for it. The downside of this is that live cache operation requires more memory. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Anna Schumaker <anna.schumaker@netapp.com> Tested-by: Steve Dickson <steved@redhat.com>
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#
a18feb55 |
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04-Apr-2018 |
David Howells <dhowells@redhat.com> |
fscache: Add tracepoints Add some tracepoints to fscache: (*) fscache_cookie - Tracks a cookie's usage count. (*) fscache_netfs - Logs registration of a network filesystem, including the pointer to the cookie allocated. (*) fscache_acquire - Logs cookie acquisition. (*) fscache_relinquish - Logs cookie relinquishment. (*) fscache_enable - Logs enablement of a cookie. (*) fscache_disable - Logs disablement of a cookie. (*) fscache_osm - Tracks execution of states in the object state machine. and cachefiles: (*) cachefiles_ref - Tracks a cachefiles object's usage count. (*) cachefiles_lookup - Logs result of lookup_one_len(). (*) cachefiles_mkdir - Logs result of vfs_mkdir(). (*) cachefiles_create - Logs result of vfs_create(). (*) cachefiles_unlink - Logs calls to vfs_unlink(). (*) cachefiles_rename - Logs calls to vfs_rename(). (*) cachefiles_mark_active - Logs an object becoming active. (*) cachefiles_wait_active - Logs a wait for an old object to be destroyed. (*) cachefiles_mark_inactive - Logs an object becoming inactive. (*) cachefiles_mark_buried - Logs the burial of an object. Signed-off-by: David Howells <dhowells@redhat.com>
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#
ac6424b9 |
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19-Jun-2017 |
Ingo Molnar <mingo@kernel.org> |
sched/wait: Rename wait_queue_t => wait_queue_entry_t Rename: wait_queue_t => wait_queue_entry_t 'wait_queue_t' was always a slight misnomer: its name implies that it's a "queue", but in reality it's a queue *entry*. The 'real' queue is the wait queue head, which had to carry the name. Start sorting this out by renaming it to 'wait_queue_entry_t'. This also allows the real structure name 'struct __wait_queue' to lose its double underscore and become 'struct wait_queue_entry', which is the more canonical nomenclature for such data types. Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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#
5d6c3191 |
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29-Sep-2016 |
Andreas Gruenbacher <agruenba@redhat.com> |
xattr: Add __vfs_{get,set,remove}xattr helpers Right now, various places in the kernel check for the existence of getxattr, setxattr, and removexattr inode operations and directly call those operations. Switch to helper functions and test for the IOP_XATTR flag instead. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Acked-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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#
a818101d |
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09-Aug-2016 |
David Howells <dhowells@redhat.com> |
cachefiles: Fix attempt to read i_blocks after deleting file [ver #2] An NULL-pointer dereference happens in cachefiles_mark_object_inactive() when it tries to read i_blocks so that it can tell the cachefilesd daemon how much space it's making available. The problem is that cachefiles_drop_object() calls cachefiles_mark_object_inactive() after calling cachefiles_delete_object() because the object being marked active staves off attempts to (re-)use the file at that filename until after it has been deleted. This means that d_inode is NULL by the time we come to try to access it. To fix the problem, have the caller of cachefiles_mark_object_inactive() supply the number of blocks freed up. Without this, the following oops may occur: BUG: unable to handle kernel NULL pointer dereference at 0000000000000098 IP: [<ffffffffa06c5cc1>] cachefiles_mark_object_inactive+0x61/0xb0 [cachefiles] ... CPU: 11 PID: 527 Comm: kworker/u64:4 Tainted: G I ------------ 3.10.0-470.el7.x86_64 #1 Hardware name: Hewlett-Packard HP Z600 Workstation/0B54h, BIOS 786G4 v03.19 03/11/2011 Workqueue: fscache_object fscache_object_work_func [fscache] task: ffff880035edaf10 ti: ffff8800b77c0000 task.ti: ffff8800b77c0000 RIP: 0010:[<ffffffffa06c5cc1>] cachefiles_mark_object_inactive+0x61/0xb0 [cachefiles] RSP: 0018:ffff8800b77c3d70 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8800bf6cc400 RCX: 0000000000000034 RDX: 0000000000000000 RSI: ffff880090ffc710 RDI: ffff8800bf761ef8 RBP: ffff8800b77c3d88 R08: 2000000000000000 R09: 0090ffc710000000 R10: ff51005d2ff1c400 R11: 0000000000000000 R12: ffff880090ffc600 R13: ffff8800bf6cc520 R14: ffff8800bf6cc400 R15: ffff8800bf6cc498 FS: 0000000000000000(0000) GS:ffff8800bb8c0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000098 CR3: 00000000019ba000 CR4: 00000000000007e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Stack: ffff880090ffc600 ffff8800bf6cc400 ffff8800867df140 ffff8800b77c3db0 ffffffffa06c48cb ffff880090ffc600 ffff880090ffc180 ffff880090ffc658 ffff8800b77c3df0 ffffffffa085d846 ffff8800a96b8150 ffff880090ffc600 Call Trace: [<ffffffffa06c48cb>] cachefiles_drop_object+0x6b/0xf0 [cachefiles] [<ffffffffa085d846>] fscache_drop_object+0xd6/0x1e0 [fscache] [<ffffffffa085d615>] fscache_object_work_func+0xa5/0x200 [fscache] [<ffffffff810a605b>] process_one_work+0x17b/0x470 [<ffffffff810a6e96>] worker_thread+0x126/0x410 [<ffffffff810a6d70>] ? rescuer_thread+0x460/0x460 [<ffffffff810ae64f>] kthread+0xcf/0xe0 [<ffffffff810ae580>] ? kthread_create_on_node+0x140/0x140 [<ffffffff81695418>] ret_from_fork+0x58/0x90 [<ffffffff810ae580>] ? kthread_create_on_node+0x140/0x140 The oopsing code shows: callq 0xffffffff810af6a0 <wake_up_bit> mov 0xf8(%r12),%rax mov 0x30(%rax),%rax mov 0x98(%rax),%rax <---- oops here lock add %rax,0x130(%rbx) where this is: d_backing_inode(object->dentry)->i_blocks Fixes: a5b3a80b899bda0f456f1246c4c5a1191ea01519 (CacheFiles: Provide read-and-reset release counters for cachefilesd) Reported-by: Jianhong Yin <jiyin@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> Reviewed-by: Steve Dickson <steved@redhat.com> cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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#
2773bf00 |
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27-Sep-2016 |
Miklos Szeredi <mszeredi@redhat.com> |
fs: rename "rename2" i_op to "rename" Generated patch: sed -i "s/\.rename2\t/\.rename\t\t/" `git grep -wl rename2` sed -i "s/\brename2\b/rename/g" `git grep -wl rename2` Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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#
18fc84da |
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27-Sep-2016 |
Miklos Szeredi <mszeredi@redhat.com> |
vfs: remove unused i_op->rename No in-tree uses remain. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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#
db20a892 |
|
03-Aug-2016 |
David Howells <dhowells@redhat.com> |
cachefiles: Fix race between inactivating and culling a cache object There's a race between cachefiles_mark_object_inactive() and cachefiles_cull(): (1) cachefiles_cull() can't delete a backing file until the cache object is marked inactive, but as soon as that's the case it's fair game. (2) cachefiles_mark_object_inactive() marks the object as being inactive and *only then* reads the i_blocks on the backing inode - but cachefiles_cull() might've managed to delete it by this point. Fix this by making sure cachefiles_mark_object_inactive() gets any data it needs from the backing inode before deactivating the object. Without this, the following oops may occur: BUG: unable to handle kernel NULL pointer dereference at 0000000000000098 IP: [<ffffffffa06c5cc1>] cachefiles_mark_object_inactive+0x61/0xb0 [cachefiles] ... CPU: 11 PID: 527 Comm: kworker/u64:4 Tainted: G I ------------ 3.10.0-470.el7.x86_64 #1 Hardware name: Hewlett-Packard HP Z600 Workstation/0B54h, BIOS 786G4 v03.19 03/11/2011 Workqueue: fscache_object fscache_object_work_func [fscache] task: ffff880035edaf10 ti: ffff8800b77c0000 task.ti: ffff8800b77c0000 RIP: 0010:[<ffffffffa06c5cc1>] cachefiles_mark_object_inactive+0x61/0xb0 [cachefiles] RSP: 0018:ffff8800b77c3d70 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8800bf6cc400 RCX: 0000000000000034 RDX: 0000000000000000 RSI: ffff880090ffc710 RDI: ffff8800bf761ef8 RBP: ffff8800b77c3d88 R08: 2000000000000000 R09: 0090ffc710000000 R10: ff51005d2ff1c400 R11: 0000000000000000 R12: ffff880090ffc600 R13: ffff8800bf6cc520 R14: ffff8800bf6cc400 R15: ffff8800bf6cc498 FS: 0000000000000000(0000) GS:ffff8800bb8c0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000098 CR3: 00000000019ba000 CR4: 00000000000007e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Stack: ffff880090ffc600 ffff8800bf6cc400 ffff8800867df140 ffff8800b77c3db0 ffffffffa06c48cb ffff880090ffc600 ffff880090ffc180 ffff880090ffc658 ffff8800b77c3df0 ffffffffa085d846 ffff8800a96b8150 ffff880090ffc600 Call Trace: [<ffffffffa06c48cb>] cachefiles_drop_object+0x6b/0xf0 [cachefiles] [<ffffffffa085d846>] fscache_drop_object+0xd6/0x1e0 [fscache] [<ffffffffa085d615>] fscache_object_work_func+0xa5/0x200 [fscache] [<ffffffff810a605b>] process_one_work+0x17b/0x470 [<ffffffff810a6e96>] worker_thread+0x126/0x410 [<ffffffff810a6d70>] ? rescuer_thread+0x460/0x460 [<ffffffff810ae64f>] kthread+0xcf/0xe0 [<ffffffff810ae580>] ? kthread_create_on_node+0x140/0x140 [<ffffffff81695418>] ret_from_fork+0x58/0x90 [<ffffffff810ae580>] ? kthread_create_on_node+0x140/0x140 The oopsing code shows: callq 0xffffffff810af6a0 <wake_up_bit> mov 0xf8(%r12),%rax mov 0x30(%rax),%rax mov 0x98(%rax),%rax <---- oops here lock add %rax,0x130(%rbx) where this is: d_backing_inode(object->dentry)->i_blocks Fixes: a5b3a80b899bda0f456f1246c4c5a1191ea01519 (CacheFiles: Provide read-and-reset release counters for cachefilesd) Reported-by: Jianhong Yin <jiyin@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> Reviewed-by: Steve Dickson <steved@redhat.com> cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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#
a5b3a80b |
|
01-Feb-2016 |
David Howells <dhowells@redhat.com> |
CacheFiles: Provide read-and-reset release counters for cachefilesd Provide read-and-reset objects- and blocks-released counters for cachefilesd to use to work out whether there's anything new that can be culled. One of the problems cachefilesd has is that if all the objects in the cache are pinned by inodes lying dormant in the kernel inode cache, there isn't anything for it to cull. In such a case, it just spins around walking the filesystem tree and scanning for something to cull. This eats up a lot of CPU time. By telling cachefilesd if there have been any releases, the daemon can sleep until there is the possibility of something to do. cachefilesd finds this information by the following means: (1) When the control fd is read, the kernel presents a list of values of interest. "freleased=N" and "breleased=N" are added to this list to indicate the number of files released and number of blocks released since the last read call. At this point the counters are reset. (2) POLLIN is signalled if the number of files released becomes greater than 0. Note that by 'released' it just means that the kernel has released its interest in those files for the moment, not necessarily that the files should be deleted from the cache. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Steve Dickson <steved@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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#
5955102c |
|
22-Jan-2016 |
Al Viro <viro@zeniv.linux.org.uk> |
wrappers for ->i_mutex access parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested}, inode_foo(inode) being mutex_foo(&inode->i_mutex). Please, use those for access to ->i_mutex; over the coming cycle ->i_mutex will become rwsem, with ->lookup() done with it held only shared. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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#
95201a40 |
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04-Nov-2015 |
NeilBrown <neilb@suse.de> |
cachefiles: perform test on s_blocksize when opening cache file. cachefiles requires that s_blocksize in the cache is not greater than PAGE_SIZE, and performs the check every time a block is accessed. Move the test to the place where the file is "opened", where other file-validity tests are performed. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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#
466b77bc |
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17-Mar-2015 |
David Howells <dhowells@redhat.com> |
VFS: fs/cachefiles: d_backing_inode() annotations Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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#
5153bc81 |
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06-Mar-2015 |
David Howells <dhowells@redhat.com> |
VFS: Cachefiles should perform fs modifications on the top layer only Cachefiles should perform fs modifications (eg. vfs_unlink()) on the top layer only and should not attempt to alter the lower layer. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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#
182d919b |
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19-Feb-2015 |
David Howells <dhowells@redhat.com> |
FS-Cache: Count culled objects and objects rejected due to lack of space Count the number of objects that get culled by the cache backend and the number of objects that the cache backend declines to instantiate due to lack of space in the cache. These numbers are made available through /proc/fs/fscache/stats Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Steve Dickson <steved@redhat.com> Acked-by: Jeff Layton <jeff.layton@primarydata.com>
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#
ce40fa78 |
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28-Jan-2015 |
David Howells <dhowells@redhat.com> |
Cachefiles: Fix up scripted S_ISDIR/S_ISREG/S_ISLNK conversions Fix up the following scripted S_ISDIR/S_ISREG/S_ISLNK conversions (or lack thereof) in cachefiles: (1) Cachefiles mostly wants to use d_can_lookup() rather than d_is_dir() as it doesn't want to deal with automounts in its cache. (2) Coccinelle didn't find S_IS* expressions in ASSERT() statements in cachefiles. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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#
e36cb0b8 |
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28-Jan-2015 |
David Howells <dhowells@redhat.com> |
VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry) Convert the following where appropriate: (1) S_ISLNK(dentry->d_inode) to d_is_symlink(dentry). (2) S_ISREG(dentry->d_inode) to d_is_reg(dentry). (3) S_ISDIR(dentry->d_inode) to d_is_dir(dentry). This is actually more complicated than it appears as some calls should be converted to d_can_lookup() instead. The difference is whether the directory in question is a real dir with a ->lookup op or whether it's a fake dir with a ->d_automount op. In some circumstances, we can subsume checks for dentry->d_inode not being NULL into this, provided we the code isn't in a filesystem that expects d_inode to be NULL if the dirent really *is* negative (ie. if we're going to use d_inode() rather than d_backing_inode() to get the inode pointer). Note that the dentry type field may be set to something other than DCACHE_MISS_TYPE when d_inode is NULL in the case of unionmount, where the VFS manages the fall-through from a negative dentry to a lower layer. In such a case, the dentry type of the negative union dentry is set to the same as the type of the lower dentry. However, if you know d_inode is not NULL at the call site, then you can use the d_is_xxx() functions even in a filesystem. There is one further complication: a 0,0 chardev dentry may be labelled DCACHE_WHITEOUT_TYPE rather than DCACHE_SPECIAL_TYPE. Strictly, this was intended for special directory entry types that don't have attached inodes. The following perl+coccinelle script was used: use strict; my @callers; open($fd, 'git grep -l \'S_IS[A-Z].*->d_inode\' |') || die "Can't grep for S_ISDIR and co. callers"; @callers = <$fd>; close($fd); unless (@callers) { print "No matches\n"; exit(0); } my @cocci = ( '@@', 'expression E;', '@@', '', '- S_ISLNK(E->d_inode->i_mode)', '+ d_is_symlink(E)', '', '@@', 'expression E;', '@@', '', '- S_ISDIR(E->d_inode->i_mode)', '+ d_is_dir(E)', '', '@@', 'expression E;', '@@', '', '- S_ISREG(E->d_inode->i_mode)', '+ d_is_reg(E)' ); my $coccifile = "tmp.sp.cocci"; open($fd, ">$coccifile") || die $coccifile; print($fd "$_\n") || die $coccifile foreach (@cocci); close($fd); foreach my $file (@callers) { chomp $file; print "Processing ", $file, "\n"; system("spatch", "--sp-file", $coccifile, $file, "--in-place", "--no-show-diff") == 0 || die "spatch failed"; } [AV: overlayfs parts skipped] Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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#
a455589f |
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21-Oct-2014 |
Al Viro <viro@zeniv.linux.org.uk> |
assorted conversions to %p[dD] Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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#
a30efe26 |
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30-Sep-2014 |
David Howells <dhowells@redhat.com> |
CacheFiles: Fix incorrect test for in-memory object collision When CacheFiles cache objects are in use, they have in-memory representations, as defined by the cachefiles_object struct. These are kept in a tree rooted in the cache and indexed by dentry pointer (since there's a unique mapping between object index key and dentry). Collisions can occur between a representation already in the tree and a new representation being set up because it takes time to dispose of an old representation - particularly if it must be unlinked or renamed. When such a collision occurs, cachefiles_mark_object_active() is meant to check to see if the old, already-present representation is in the process of being discarded (ie. FSCACHE_OBJECT_IS_LIVE is not set on it) - and, if so, wait for the representation to be removed (ie. CACHEFILES_OBJECT_ACTIVE is then cleared). However, the test for whether the old representation is still live is checking the new object - which always will be live at this point. This leads to an oops looking like: CacheFiles: Error: Unexpected object collision object: OBJ1b354 objstate=LOOK_UP_OBJECT fl=8 wbusy=2 ev=0[0] ops=0 inp=0 exc=0 parent=ffff88053f5417c0 cookie=ffff880538f202a0 [pr=ffff8805381b7160 nd=ffff880509c6eb78 fl=27] key=[8] '2490000000000000' xobject: OBJ1a600 xobjstate=DROP_OBJECT fl=70 wbusy=2 ev=0[0] xops=0 inp=0 exc=0 xparent=ffff88053f5417c0 xcookie=ffff88050f4cbf70 [pr=ffff8805381b7160 nd= (null) fl=12] ------------[ cut here ]------------ kernel BUG at fs/cachefiles/namei.c:200! ... Workqueue: fscache_object fscache_object_work_func [fscache] ... RIP: ... cachefiles_walk_to_object+0x7ea/0x860 [cachefiles] ... Call Trace: [<ffffffffa04dadd8>] ? cachefiles_lookup_object+0x58/0x100 [cachefiles] [<ffffffffa01affe9>] ? fscache_look_up_object+0xb9/0x1d0 [fscache] [<ffffffffa01afc4d>] ? fscache_parent_ready+0x2d/0x80 [fscache] [<ffffffffa01b0672>] ? fscache_object_work_func+0x92/0x1f0 [fscache] [<ffffffff8107e82b>] ? process_one_work+0x16b/0x400 [<ffffffff8107fc16>] ? worker_thread+0x116/0x380 [<ffffffff8107fb00>] ? manage_workers.isra.21+0x290/0x290 [<ffffffff81085edc>] ? kthread+0xbc/0xe0 [<ffffffff81085e20>] ? flush_kthread_worker+0x80/0x80 [<ffffffff81502d0c>] ? ret_from_fork+0x7c/0xb0 [<ffffffff81085e20>] ? flush_kthread_worker+0x80/0x80 Reported-by: Manuel Schölling <manuel.schoelling@gmx.de> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com>
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#
6ff66ac7 |
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25-Sep-2014 |
Fabian Frederick <fabf@skynet.be> |
fs/cachefiles: add missing \n to kerror conversions Commit 0227d6abb378 ("fs/cachefiles: replace kerror by pr_err") didn't include newline featuring in original kerror definition Signed-off-by: Fabian Frederick <fabf@skynet.be> Reported-by: David Howells <dhowells@redhat.com> Acked-by: David Howells <dhowells@redhat.com> Cc: <stable@vger.kernel.org> [3.16.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
e2cf1f1c |
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17-Sep-2014 |
David Howells <dhowells@redhat.com> |
CacheFiles: Handle rename2 Not all filesystems now provide the rename i_op - ext4 for one - but rather provide the rename2 i_op. CacheFiles checks that the filesystem has rename and so will reject ext4 now with EPERM: CacheFiles: Failed to register: -1 Fix this by checking for rename2 as an alternative. The call to vfs_rename() actually handles selection of the appropriate function, so we needn't worry about that. Turning on debugging shows: [cachef] ==> cachefiles_get_directory(,,cache) [cachef] subdir -> ffff88000b22b778 positive [cachef] <== cachefiles_get_directory() = -1 [check] where -1 is EPERM. Signed-off-by: David Howells <dhowells@redhat.com>
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#
0227d6ab |
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06-Jun-2014 |
Fabian Frederick <fabf@skynet.be> |
fs/cachefiles: replace kerror by pr_err Also add pr_fmt in internal.h Signed-off-by: Fabian Frederick <fabf@skynet.be> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
4e1eb883 |
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06-Jun-2014 |
Fabian Frederick <fabf@skynet.be> |
FS/CACHEFILES: convert printk to pr_foo() Signed-off-by: Fabian Frederick <fabf@skynet.be> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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627bf81a |
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01-Feb-2014 |
Al Viro <viro@zeniv.linux.org.uk> |
get rid of pointless checks for NULL ->i_op Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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#
0b3974eb |
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01-Apr-2014 |
Miklos Szeredi <mszeredi@suse.cz> |
security: add flags to rename hooks Add flags to security_path_rename() and security_inode_rename() hooks. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: J. Bruce Fields <bfields@redhat.com>
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520c8b16 |
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01-Apr-2014 |
Miklos Szeredi <mszeredi@suse.cz> |
vfs: add renameat2 syscall Add new renameat2 syscall, which is the same as renameat with an added flags argument. Pass flags to vfs_rename() and to i_op->rename() as well. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: J. Bruce Fields <bfields@redhat.com>
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8e6d782c |
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20-Sep-2011 |
J. Bruce Fields <bfields@redhat.com> |
locks: break delegations on rename Cc: David Howells <dhowells@redhat.com> Acked-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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b21996e3 |
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20-Sep-2011 |
J. Bruce Fields <bfields@redhat.com> |
locks: break delegations on unlink We need to break delegations on any operation that changes the set of links pointing to an inode. Start with unlink. Such operations also hold the i_mutex on a parent directory. Breaking a delegation may require waiting for a timeout (by default 90 seconds) in the case of a unresponsive NFS client. To avoid blocking all directory operations, we therefore drop locks before waiting for the delegation. The logic then looks like: acquire locks ... test for delegation; if found: take reference on inode release locks wait for delegation break drop reference on inode retry It is possible this could never terminate. (Even if we take precautions to prevent another delegation being acquired on the same inode, we could get a different inode on each retry.) But this seems very unlikely. The initial test for a delegation happens after the lock on the target inode is acquired, but the directory inode may have been acquired further up the call stack. We therefore add a "struct inode **" argument to any intervening functions, which we use to pass the inode back up to the caller in the case it needs a delegation synchronously broken. Cc: David Howells <dhowells@redhat.com> Cc: Tyler Hicks <tyhicks@canonical.com> Cc: Dustin Kirkland <dustin.kirkland@gazzang.com> Acked-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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509bf24d |
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20-Sep-2013 |
David Howells <dhowells@redhat.com> |
CacheFiles: Don't try to dump the index key if the cookie has been cleared Don't try to dump the index key that distinguishes an object if netfs data in the cookie the object refers to has been cleared (ie. the cookie has passed most of the way through __fscache_relinquish_cookie()). Since the netfs holds the index key, we can't get at it once the ->def and ->netfs_data pointers have been cleared - and a NULL pointer exception will ensue, usually just after a: CacheFiles: Error: Unexpected object collision error is reported. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
caaef690 |
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10-May-2013 |
David Howells <dhowells@redhat.com> |
FS-Cache: Fix object state machine to have separate work and wait states Fix object state machine to have separate work and wait states as that makes it easier to envision. There are now three kinds of state: (1) Work state. This is an execution state. No event processing is performed by a work state. The function attached to a work state returns a pointer indicating the next state to which the OSM should transition. Returning NO_TRANSIT repeats the current state, but goes back to the scheduler first. (2) Wait state. This is an event processing state. No execution is performed by a wait state. Wait states are just tables of "if event X occurs, clear it and transition to state Y". The dispatcher returns to the scheduler if none of the events in which the wait state has an interest are currently pending. (3) Out-of-band state. This is a special work state. Transitions to normal states can be overridden when an unexpected event occurs (eg. I/O error). Instead the dispatcher disables and clears the OOB event and transits to the specified work state. This then acts as an ordinary work state, though object->state points to the overridden destination. Returning NO_TRANSIT resumes the overridden transition. In addition, the states have names in their definitions, so there's no need for tables of state names. Further, the EV_REQUEUE event is no longer necessary as that is automatic for work states. Since the states are now separate structs rather than values in an enum, it's not possible to use comparisons other than (non-)equality between them, so use some object->flags to indicate what phase an object is in. The EV_RELEASE, EV_RETIRE and EV_WITHDRAW events have been squished into one (EV_KILL). An object flag now carries the information about retirement. Similarly, the RELEASING, RECYCLING and WITHDRAWING states have been merged into an KILL_OBJECT state and additional states have been added for handling waiting dependent objects (JUMPSTART_DEPS and KILL_DEPENDENTS). A state has also been added for synchronising with parent object initialisation (WAIT_FOR_PARENT) and another for initiating look up (PARENT_READY). Signed-off-by: David Howells <dhowells@redhat.com> Tested-By: Milosz Tanski <milosz@adfin.com> Acked-by: Jeff Layton <jlayton@redhat.com>
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493f7bc1 |
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10-May-2013 |
David Howells <dhowells@redhat.com> |
FS-Cache: Wrap checks on object state Wrap checks on object state (mostly outside of fs/fscache/object.c) with inline functions so that the mechanism can be replaced. Some of the state checks within object.c are left as-is as they will be replaced. Signed-off-by: David Howells <dhowells@redhat.com> Tested-By: Milosz Tanski <milosz@adfin.com> Acked-by: Jeff Layton <jlayton@redhat.com>
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#
6bd5e82b |
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10-May-2013 |
J. Bruce Fields <bfields@redhat.com> |
CacheFiles: name i_mutex lock class explicitly Just some cleanup. (And note the caller of this function may, for example, call vfs_unlink on a child, so the "1" (I_MUTEX_PARENT) really was what was intended here.) Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-By: Milosz Tanski <milosz@adfin.com> Acked-by: Jeff Layton <jlayton@redhat.com>
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c2d35bfe |
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05-Dec-2012 |
David Howells <dhowells@redhat.com> |
FS-Cache: Don't mask off the object event mask when printing it Don't mask off the object event mask when printing it. That way it can be seen if threre are bits set that shouldn't be. Signed-off-by: David Howells <dhowells@redhat.com>
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312b63fb |
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10-Jun-2012 |
Al Viro <viro@zeniv.linux.org.uk> |
don't pass nameidata * to vfs_create() all we want is a boolean flag, same as the method gets now Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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#
68ac1234 |
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15-Mar-2012 |
Al Viro <viro@zeniv.linux.org.uk> |
switch touch_atime to struct path Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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#
82140443 |
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24-Dec-2010 |
David Howells <dhowells@redhat.com> |
CacheFiles: Add calls to path-based security hooks Add calls to path-based security hooks into CacheFiles as, unlike inode-based security, these aren't implicit in the vfs_mkdir() and similar calls. Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
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#
8b8edefa |
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20-Jul-2010 |
Tejun Heo <tj@kernel.org> |
fscache: convert object to use workqueue instead of slow-work Make fscache object state transition callbacks use workqueue instead of slow-work. New dedicated unbound CPU workqueue fscache_object_wq is created. get/put callbacks are renamed and modified to take @object and called directly from the enqueue wrapper and the work function. While at it, make all open coded instances of get/put to use fscache_get/put_object(). * Unbound workqueue is used. * work_busy() output is printed instead of slow-work flags in object debugging outputs. They mean basically the same thing bit-for-bit. * sysctl fscache.object_max_active added to control concurrency. The default value is nr_cpus clamped between 4 and WQ_UNBOUND_MAX_ACTIVE. * slow_work_sleep_till_thread_needed() is replaced with fscache private implementation fscache_object_sleep_till_congested() which waits on fscache_object_wq congestion. * debugfs support is dropped for now. Tracing API based debug facility is planned to be added. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: David Howells <dhowells@redhat.com>
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c61ea31d |
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11-May-2010 |
David Howells <dhowells@redhat.com> |
CacheFiles: Fix occasional EIO on call to vfs_unlink() Fix an occasional EIO returned by a call to vfs_unlink(): [ 4868.465413] CacheFiles: I/O Error: Unlink failed [ 4868.465444] FS-Cache: Cache cachefiles stopped due to I/O error [ 4947.320011] CacheFiles: File cache on md3 unregistering [ 4947.320041] FS-Cache: Withdrawing cache "mycache" [ 5127.348683] FS-Cache: Cache "mycache" added (type cachefiles) [ 5127.348716] CacheFiles: File cache on md3 registered [ 7076.871081] CacheFiles: I/O Error: Unlink failed [ 7076.871130] FS-Cache: Cache cachefiles stopped due to I/O error [ 7116.780891] CacheFiles: File cache on md3 unregistering [ 7116.780937] FS-Cache: Withdrawing cache "mycache" [ 7296.813394] FS-Cache: Cache "mycache" added (type cachefiles) [ 7296.813432] CacheFiles: File cache on md3 registered What happens is this: (1) A cached NFS file is seen to have become out of date, so NFS retires the object and immediately acquires a new object with the same key. (2) Retirement of the old object is done asynchronously - so the lookup/create to generate the new object may be done first. This can be a problem as the old object and the new object must exist at the same point in the backing filesystem (i.e. they must have the same pathname). (3) The lookup for the new object sees that a backing file already exists, checks to see whether it is valid and sees that it isn't. It then deletes that file and creates a new one on disk. (4) The retirement phase for the old file is then performed. It tries to delete the dentry it has, but ext4_unlink() returns -EIO because the inode attached to that dentry no longer matches the inode number associated with the filename in the parent directory. The trace below shows this quite well. [md5sum] ==> __fscache_relinquish_cookie(ffff88002d12fb58{NFS.fh,ffff88002ce62100},1) [md5sum] ==> __fscache_acquire_cookie({NFS.server},{NFS.fh},ffff88002ce62100) NFS has retired the old cookie and asked for a new one. [kslowd] ==> fscache_object_state_machine({OBJ52,OBJECT_ACTIVE,24}) [kslowd] <== fscache_object_state_machine() [->OBJECT_DYING] [kslowd] ==> fscache_object_state_machine({OBJ53,OBJECT_INIT,0}) [kslowd] <== fscache_object_state_machine() [->OBJECT_LOOKING_UP] [kslowd] ==> fscache_object_state_machine({OBJ52,OBJECT_DYING,24}) [kslowd] <== fscache_object_state_machine() [->OBJECT_RECYCLING] The old object (OBJ52) is going through the terminal states to get rid of it, whilst the new object - (OBJ53) - is coming into being. [kslowd] ==> fscache_object_state_machine({OBJ53,OBJECT_LOOKING_UP,0}) [kslowd] ==> cachefiles_walk_to_object({ffff88003029d8b8},OBJ53,@68,) [kslowd] lookup '@68' [kslowd] next -> ffff88002ce41bd0 positive [kslowd] advance [kslowd] lookup 'Es0g00og0_Nd_XCYe3BOzvXrsBLMlN6aw16M1htaA' [kslowd] next -> ffff8800369faac8 positive The new object has looked up the subdir in which the file would be in (getting dentry ffff88002ce41bd0) and then looked up the file itself (getting dentry ffff8800369faac8). [kslowd] validate 'Es0g00og0_Nd_XCYe3BOzvXrsBLMlN6aw16M1htaA' [kslowd] ==> cachefiles_bury_object(,'@68','Es0g00og0_Nd_XCYe3BOzvXrsBLMlN6aw16M1htaA') [kslowd] remove ffff8800369faac8 from ffff88002ce41bd0 [kslowd] unlink stale object [kslowd] <== cachefiles_bury_object() = 0 It then checks the file's xattrs to see if it's valid. NFS says that the auxiliary data indicate the file is out of date (obvious to us - that's why NFS ditched the old version and got a new one). CacheFiles then deletes the old file (dentry ffff8800369faac8). [kslowd] redo lookup [kslowd] lookup 'Es0g00og0_Nd_XCYe3BOzvXrsBLMlN6aw16M1htaA' [kslowd] next -> ffff88002cd94288 negative [kslowd] create -> ffff88002cd94288{ffff88002cdaf238{ino=148247}} CacheFiles then redoes the lookup and gets a negative result in a new dentry (ffff88002cd94288) which it then creates a file for. [kslowd] ==> cachefiles_mark_object_active(,OBJ53) [kslowd] <== cachefiles_mark_object_active() = 0 [kslowd] === OBTAINED_OBJECT === [kslowd] <== cachefiles_walk_to_object() = 0 [148247] [kslowd] <== fscache_object_state_machine() [->OBJECT_AVAILABLE] The new object is then marked active and the state machine moves to the available state - at which point NFS can start filling the object. [kslowd] ==> fscache_object_state_machine({OBJ52,OBJECT_RECYCLING,20}) [kslowd] ==> fscache_release_object() [kslowd] ==> cachefiles_drop_object({OBJ52,2}) [kslowd] ==> cachefiles_delete_object(,OBJ52{ffff8800369faac8}) The old object, meanwhile, goes on with being retired. If allocation occurs first, cachefiles_delete_object() has to wait for dir->d_inode->i_mutex to become available before it can continue. [kslowd] ==> cachefiles_bury_object(,'@68','Es0g00og0_Nd_XCYe3BOzvXrsBLMlN6aw16M1htaA') [kslowd] remove ffff8800369faac8 from ffff88002ce41bd0 [kslowd] unlink stale object EXT4-fs warning (device sda6): ext4_unlink: Inode number mismatch in unlink (148247!=148193) CacheFiles: I/O Error: Unlink failed FS-Cache: Cache cachefiles stopped due to I/O error CacheFiles then tries to delete the file for the old object, but the dentry it has (ffff8800369faac8) no longer points to a valid inode for that directory entry, and so ext4_unlink() returns -EIO when de->inode does not match i_ino. [kslowd] <== cachefiles_bury_object() = -5 [kslowd] <== cachefiles_delete_object() = -5 [kslowd] <== fscache_object_state_machine() [->OBJECT_DEAD] [kslowd] ==> fscache_object_state_machine({OBJ53,OBJECT_AVAILABLE,0}) [kslowd] <== fscache_object_state_machine() [->OBJECT_ACTIVE] (Note that the above trace includes extra information beyond that produced by the upstream code). The fix is to note when an object that is being retired has had its object deleted preemptively by a replacement object that is being created, and to skip the second removal attempt in such a case. Reported-by: Greg M <gregm@servu.net.au> Reported-by: Mark Moseley <moseleymark@gmail.com> Reported-by: Romain DEGEZ <romain.degez@smartjog.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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5a0e3ad6 |
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24-Mar-2010 |
Tejun Heo <tj@kernel.org> |
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
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8f9941ae |
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19-Feb-2010 |
David Howells <dhowells@redhat.com> |
CacheFiles: Fix a race in cachefiles_delete_object() vs rename cachefiles_delete_object() can race with rename. It gets the parent directory of the object it's asked to delete, then locks it - but rename may have changed the object's parent between the get and the completion of the lock. However, if such a circumstance is detected, we abandon our attempt to delete the object - since it's no longer in the index key path, it won't be seen again by lookups of that key. The assumption is that cachefilesd may have culled it by renaming it to the graveyard for later destruction. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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fee096de |
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19-Nov-2009 |
David Howells <dhowells@redhat.com> |
CacheFiles: Catch an overly long wait for an old active object Catch an overly long wait for an old, dying active object when we want to replace it with a new one. The probability is that all the slow-work threads are hogged, and the delete can't get a look in. What we do instead is: (1) if there's nothing in the slow work queue, we sleep until either the dying object has finished dying or there is something in the slow work queue behind which we can queue our object. (2) if there is something in the slow work queue, we return ETIMEDOUT to fscache_lookup_object(), which then puts us back on the slow work queue, presumably behind the deletion that we're blocked by. We are then deferred for a while until we work our way back through the queue - without blocking a slow-work thread unnecessarily. A backtrace similar to the following may appear in the log without this patch: INFO: task kslowd004:5711 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kslowd004 D 0000000000000000 0 5711 2 0x00000080 ffff88000340bb80 0000000000000046 ffff88002550d000 0000000000000000 ffff88002550d000 0000000000000007 ffff88000340bfd8 ffff88002550d2a8 000000000000ddf0 00000000000118c0 00000000000118c0 ffff88002550d2a8 Call Trace: [<ffffffff81058e21>] ? trace_hardirqs_on+0xd/0xf [<ffffffffa011c4d8>] ? cachefiles_wait_bit+0x0/0xd [cachefiles] [<ffffffffa011c4e1>] cachefiles_wait_bit+0x9/0xd [cachefiles] [<ffffffff81353153>] __wait_on_bit+0x43/0x76 [<ffffffff8111ae39>] ? ext3_xattr_get+0x1ec/0x270 [<ffffffff813531ef>] out_of_line_wait_on_bit+0x69/0x74 [<ffffffffa011c4d8>] ? cachefiles_wait_bit+0x0/0xd [cachefiles] [<ffffffff8104c125>] ? wake_bit_function+0x0/0x2e [<ffffffffa011bc79>] cachefiles_mark_object_active+0x203/0x23b [cachefiles] [<ffffffffa011c209>] cachefiles_walk_to_object+0x558/0x827 [cachefiles] [<ffffffffa011a429>] cachefiles_lookup_object+0xac/0x12a [cachefiles] [<ffffffffa00aa1e9>] fscache_lookup_object+0x1c7/0x214 [fscache] [<ffffffffa00aafc5>] fscache_object_state_machine+0xa5/0x52d [fscache] [<ffffffffa00ab4ac>] fscache_object_slow_work_execute+0x5f/0xa0 [fscache] [<ffffffff81082093>] slow_work_execute+0x18f/0x2d1 [<ffffffff8108239a>] slow_work_thread+0x1c5/0x308 [<ffffffff8104c0f1>] ? autoremove_wake_function+0x0/0x34 [<ffffffff810821d5>] ? slow_work_thread+0x0/0x308 [<ffffffff8104be91>] kthread+0x7a/0x82 [<ffffffff8100beda>] child_rip+0xa/0x20 [<ffffffff8100b87c>] ? restore_args+0x0/0x30 [<ffffffff8104be17>] ? kthread+0x0/0x82 [<ffffffff8100bed0>] ? child_rip+0x0/0x20 1 lock held by kslowd004/5711: #0: (&sb->s_type->i_mutex_key#7/1){+.+.+.}, at: [<ffffffffa011be64>] cachefiles_walk_to_object+0x1b3/0x827 [cachefiles] Signed-off-by: David Howells <dhowells@redhat.com>
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d0e27b78 |
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19-Nov-2009 |
David Howells <dhowells@redhat.com> |
CacheFiles: Better showing of debugging information in active object problems Show more debugging information if cachefiles_mark_object_active() is asked to activate an active object. This may happen, for instance, if the netfs tries to register an object with the same key multiple times. The code is changed to (a) get the appropriate object lock to protect the cookie pointer whilst we dereference it, and (b) get and display the cookie key if available. Signed-off-by: David Howells <dhowells@redhat.com>
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6511de33 |
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19-Nov-2009 |
David Howells <dhowells@redhat.com> |
CacheFiles: Mark parent directory locks as I_MUTEX_PARENT to keep lockdep happy Mark parent directory locks as I_MUTEX_PARENT in the callers of cachefiles_bury_object() so that lockdep doesn't complain when that invokes vfs_unlink(): ============================================= [ INFO: possible recursive locking detected ] 2.6.32-rc6-cachefs #47 --------------------------------------------- kslowd002/3089 is trying to acquire lock: (&sb->s_type->i_mutex_key#7){+.+.+.}, at: [<ffffffff810bbf72>] vfs_unlink+0x8b/0x128 but task is already holding lock: (&sb->s_type->i_mutex_key#7){+.+.+.}, at: [<ffffffffa00e4e61>] cachefiles_walk_to_object+0x1b0/0x831 [cachefiles] other info that might help us debug this: 1 lock held by kslowd002/3089: #0: (&sb->s_type->i_mutex_key#7){+.+.+.}, at: [<ffffffffa00e4e61>] cachefiles_walk_to_object+0x1b0/0x831 [cachefiles] stack backtrace: Pid: 3089, comm: kslowd002 Not tainted 2.6.32-rc6-cachefs #47 Call Trace: [<ffffffff8105ad7b>] __lock_acquire+0x1649/0x16e3 [<ffffffff8118170e>] ? inode_has_perm+0x5f/0x61 [<ffffffff8105ae6c>] lock_acquire+0x57/0x6d [<ffffffff810bbf72>] ? vfs_unlink+0x8b/0x128 [<ffffffff81353ac3>] mutex_lock_nested+0x54/0x292 [<ffffffff810bbf72>] ? vfs_unlink+0x8b/0x128 [<ffffffff8118179e>] ? selinux_inode_permission+0x8e/0x90 [<ffffffff8117e271>] ? security_inode_permission+0x1c/0x1e [<ffffffff810bb4fb>] ? inode_permission+0x99/0xa5 [<ffffffff810bbf72>] vfs_unlink+0x8b/0x128 [<ffffffff810adb19>] ? kfree+0xed/0xf9 [<ffffffffa00e3f00>] cachefiles_bury_object+0xb6/0x420 [cachefiles] [<ffffffff81058e21>] ? trace_hardirqs_on+0xd/0xf [<ffffffffa00e7e24>] ? cachefiles_check_object_xattr+0x233/0x293 [cachefiles] [<ffffffffa00e51b0>] cachefiles_walk_to_object+0x4ff/0x831 [cachefiles] [<ffffffff81032238>] ? finish_task_switch+0x0/0xb2 [<ffffffffa00e3429>] cachefiles_lookup_object+0xac/0x12a [cachefiles] [<ffffffffa00741e9>] fscache_lookup_object+0x1c7/0x214 [fscache] [<ffffffffa0074fc5>] fscache_object_state_machine+0xa5/0x52d [fscache] [<ffffffffa00754ac>] fscache_object_slow_work_execute+0x5f/0xa0 [fscache] [<ffffffff81082093>] slow_work_execute+0x18f/0x2d1 [<ffffffff8108239a>] slow_work_thread+0x1c5/0x308 [<ffffffff8104c0f1>] ? autoremove_wake_function+0x0/0x34 [<ffffffff810821d5>] ? slow_work_thread+0x0/0x308 [<ffffffff8104be91>] kthread+0x7a/0x82 [<ffffffff8100beda>] child_rip+0xa/0x20 [<ffffffff8100b87c>] ? restore_args+0x0/0x30 [<ffffffff8104be17>] ? kthread+0x0/0x82 [<ffffffff8100bed0>] ? child_rip+0x0/0x20 Signed-off-by: Daivd Howells <dhowells@redhat.com>
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9ae326a6 |
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03-Apr-2009 |
David Howells <dhowells@redhat.com> |
CacheFiles: A cache that backs onto a mounted filesystem Add an FS-Cache cache-backend that permits a mounted filesystem to be used as a backing store for the cache. CacheFiles uses a userspace daemon to do some of the cache management - such as reaping stale nodes and culling. This is called cachefilesd and lives in /sbin. The source for the daemon can be downloaded from: http://people.redhat.com/~dhowells/cachefs/cachefilesd.c And an example configuration from: http://people.redhat.com/~dhowells/cachefs/cachefilesd.conf The filesystem and data integrity of the cache are only as good as those of the filesystem providing the backing services. Note that CacheFiles does not attempt to journal anything since the journalling interfaces of the various filesystems are very specific in nature. CacheFiles creates a misc character device - "/dev/cachefiles" - that is used to communication with the daemon. Only one thing may have this open at once, and whilst it is open, a cache is at least partially in existence. The daemon opens this and sends commands down it to control the cache. CacheFiles is currently limited to a single cache. CacheFiles attempts to maintain at least a certain percentage of free space on the filesystem, shrinking the cache by culling the objects it contains to make space if necessary - see the "Cache Culling" section. This means it can be placed on the same medium as a live set of data, and will expand to make use of spare space and automatically contract when the set of data requires more space. ============ REQUIREMENTS ============ The use of CacheFiles and its daemon requires the following features to be available in the system and in the cache filesystem: - dnotify. - extended attributes (xattrs). - openat() and friends. - bmap() support on files in the filesystem (FIBMAP ioctl). - The use of bmap() to detect a partial page at the end of the file. It is strongly recommended that the "dir_index" option is enabled on Ext3 filesystems being used as a cache. ============= CONFIGURATION ============= The cache is configured by a script in /etc/cachefilesd.conf. These commands set up cache ready for use. The following script commands are available: (*) brun <N>% (*) bcull <N>% (*) bstop <N>% (*) frun <N>% (*) fcull <N>% (*) fstop <N>% Configure the culling limits. Optional. See the section on culling The defaults are 7% (run), 5% (cull) and 1% (stop) respectively. The commands beginning with a 'b' are file space (block) limits, those beginning with an 'f' are file count limits. (*) dir <path> Specify the directory containing the root of the cache. Mandatory. (*) tag <name> Specify a tag to FS-Cache to use in distinguishing multiple caches. Optional. The default is "CacheFiles". (*) debug <mask> Specify a numeric bitmask to control debugging in the kernel module. Optional. The default is zero (all off). The following values can be OR'd into the mask to collect various information: 1 Turn on trace of function entry (_enter() macros) 2 Turn on trace of function exit (_leave() macros) 4 Turn on trace of internal debug points (_debug()) This mask can also be set through sysfs, eg: echo 5 >/sys/modules/cachefiles/parameters/debug ================== STARTING THE CACHE ================== The cache is started by running the daemon. The daemon opens the cache device, configures the cache and tells it to begin caching. At that point the cache binds to fscache and the cache becomes live. The daemon is run as follows: /sbin/cachefilesd [-d]* [-s] [-n] [-f <configfile>] The flags are: (*) -d Increase the debugging level. This can be specified multiple times and is cumulative with itself. (*) -s Send messages to stderr instead of syslog. (*) -n Don't daemonise and go into background. (*) -f <configfile> Use an alternative configuration file rather than the default one. =============== THINGS TO AVOID =============== Do not mount other things within the cache as this will cause problems. The kernel module contains its own very cut-down path walking facility that ignores mountpoints, but the daemon can't avoid them. Do not create, rename or unlink files and directories in the cache whilst the cache is active, as this may cause the state to become uncertain. Renaming files in the cache might make objects appear to be other objects (the filename is part of the lookup key). Do not change or remove the extended attributes attached to cache files by the cache as this will cause the cache state management to get confused. Do not create files or directories in the cache, lest the cache get confused or serve incorrect data. Do not chmod files in the cache. The module creates things with minimal permissions to prevent random users being able to access them directly. ============= CACHE CULLING ============= The cache may need culling occasionally to make space. This involves discarding objects from the cache that have been used less recently than anything else. Culling is based on the access time of data objects. Empty directories are culled if not in use. Cache culling is done on the basis of the percentage of blocks and the percentage of files available in the underlying filesystem. There are six "limits": (*) brun (*) frun If the amount of free space and the number of available files in the cache rises above both these limits, then culling is turned off. (*) bcull (*) fcull If the amount of available space or the number of available files in the cache falls below either of these limits, then culling is started. (*) bstop (*) fstop If the amount of available space or the number of available files in the cache falls below either of these limits, then no further allocation of disk space or files is permitted until culling has raised things above these limits again. These must be configured thusly: 0 <= bstop < bcull < brun < 100 0 <= fstop < fcull < frun < 100 Note that these are percentages of available space and available files, and do _not_ appear as 100 minus the percentage displayed by the "df" program. The userspace daemon scans the cache to build up a table of cullable objects. These are then culled in least recently used order. A new scan of the cache is started as soon as space is made in the table. Objects will be skipped if their atimes have changed or if the kernel module says it is still using them. =============== CACHE STRUCTURE =============== The CacheFiles module will create two directories in the directory it was given: (*) cache/ (*) graveyard/ The active cache objects all reside in the first directory. The CacheFiles kernel module moves any retired or culled objects that it can't simply unlink to the graveyard from which the daemon will actually delete them. The daemon uses dnotify to monitor the graveyard directory, and will delete anything that appears therein. The module represents index objects as directories with the filename "I..." or "J...". Note that the "cache/" directory is itself a special index. Data objects are represented as files if they have no children, or directories if they do. Their filenames all begin "D..." or "E...". If represented as a directory, data objects will have a file in the directory called "data" that actually holds the data. Special objects are similar to data objects, except their filenames begin "S..." or "T...". If an object has children, then it will be represented as a directory. Immediately in the representative directory are a collection of directories named for hash values of the child object keys with an '@' prepended. Into this directory, if possible, will be placed the representations of the child objects: INDEX INDEX INDEX DATA FILES ========= ========== ================================= ================ cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400 cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...DB1ry cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...N22ry cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...FP1ry If the key is so long that it exceeds NAME_MAX with the decorations added on to it, then it will be cut into pieces, the first few of which will be used to make a nest of directories, and the last one of which will be the objects inside the last directory. The names of the intermediate directories will have '+' prepended: J1223/@23/+xy...z/+kl...m/Epqr Note that keys are raw data, and not only may they exceed NAME_MAX in size, they may also contain things like '/' and NUL characters, and so they may not be suitable for turning directly into a filename. To handle this, CacheFiles will use a suitably printable filename directly and "base-64" encode ones that aren't directly suitable. The two versions of object filenames indicate the encoding: OBJECT TYPE PRINTABLE ENCODED =============== =============== =============== Index "I..." "J..." Data "D..." "E..." Special "S..." "T..." Intermediate directories are always "@" or "+" as appropriate. Each object in the cache has an extended attribute label that holds the object type ID (required to distinguish special objects) and the auxiliary data from the netfs. The latter is used to detect stale objects in the cache and update or retire them. Note that CacheFiles will erase from the cache any file it doesn't recognise or any file of an incorrect type (such as a FIFO file or a device file). ========================== SECURITY MODEL AND SELINUX ========================== CacheFiles is implemented to deal properly with the LSM security features of the Linux kernel and the SELinux facility. One of the problems that CacheFiles faces is that it is generally acting on behalf of a process, and running in that process's context, and that includes a security context that is not appropriate for accessing the cache - either because the files in the cache are inaccessible to that process, or because if the process creates a file in the cache, that file may be inaccessible to other processes. The way CacheFiles works is to temporarily change the security context (fsuid, fsgid and actor security label) that the process acts as - without changing the security context of the process when it the target of an operation performed by some other process (so signalling and suchlike still work correctly). When the CacheFiles module is asked to bind to its cache, it: (1) Finds the security label attached to the root cache directory and uses that as the security label with which it will create files. By default, this is: cachefiles_var_t (2) Finds the security label of the process which issued the bind request (presumed to be the cachefilesd daemon), which by default will be: cachefilesd_t and asks LSM to supply a security ID as which it should act given the daemon's label. By default, this will be: cachefiles_kernel_t SELinux transitions the daemon's security ID to the module's security ID based on a rule of this form in the policy. type_transition <daemon's-ID> kernel_t : process <module's-ID>; For instance: type_transition cachefilesd_t kernel_t : process cachefiles_kernel_t; The module's security ID gives it permission to create, move and remove files and directories in the cache, to find and access directories and files in the cache, to set and access extended attributes on cache objects, and to read and write files in the cache. The daemon's security ID gives it only a very restricted set of permissions: it may scan directories, stat files and erase files and directories. It may not read or write files in the cache, and so it is precluded from accessing the data cached therein; nor is it permitted to create new files in the cache. There are policy source files available in: http://people.redhat.com/~dhowells/fscache/cachefilesd-0.8.tar.bz2 and later versions. In that tarball, see the files: cachefilesd.te cachefilesd.fc cachefilesd.if They are built and installed directly by the RPM. If a non-RPM based system is being used, then copy the above files to their own directory and run: make -f /usr/share/selinux/devel/Makefile semodule -i cachefilesd.pp You will need checkpolicy and selinux-policy-devel installed prior to the build. By default, the cache is located in /var/fscache, but if it is desirable that it should be elsewhere, than either the above policy files must be altered, or an auxiliary policy must be installed to label the alternate location of the cache. For instructions on how to add an auxiliary policy to enable the cache to be located elsewhere when SELinux is in enforcing mode, please see: /usr/share/doc/cachefilesd-*/move-cache.txt When the cachefilesd rpm is installed; alternatively, the document can be found in the sources. ================== A NOTE ON SECURITY ================== CacheFiles makes use of the split security in the task_struct. It allocates its own task_security structure, and redirects current->act_as to point to it when it acts on behalf of another process, in that process's context. The reason it does this is that it calls vfs_mkdir() and suchlike rather than bypassing security and calling inode ops directly. Therefore the VFS and LSM may deny the CacheFiles access to the cache data because under some circumstances the caching code is running in the security context of whatever process issued the original syscall on the netfs. Furthermore, should CacheFiles create a file or directory, the security parameters with that object is created (UID, GID, security label) would be derived from that process that issued the system call, thus potentially preventing other processes from accessing the cache - including CacheFiles's cache management daemon (cachefilesd). What is required is to temporarily override the security of the process that issued the system call. We can't, however, just do an in-place change of the security data as that affects the process as an object, not just as a subject. This means it may lose signals or ptrace events for example, and affects what the process looks like in /proc. So CacheFiles makes use of a logical split in the security between the objective security (task->sec) and the subjective security (task->act_as). The objective security holds the intrinsic security properties of a process and is never overridden. This is what appears in /proc, and is what is used when a process is the target of an operation by some other process (SIGKILL for example). The subjective security holds the active security properties of a process, and may be overridden. This is not seen externally, and is used whan a process acts upon another object, for example SIGKILLing another process or opening a file. LSM hooks exist that allow SELinux (or Smack or whatever) to reject a request for CacheFiles to run in a context of a specific security label, or to create files and directories with another security label. This documentation is added by the patch to: Documentation/filesystems/caching/cachefiles.txt Signed-Off-By: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
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