nilfs2: convert metadata file common code to use kmap_local

In the common code of metadata files, the new block creation routine
nilfs_mdt_insert_new_block() still uses the deprecated kmap_atomic(), so
convert it to use kmap_local.

Link: https://lkml.kernel.org/r/20240122140202.6950-5-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

nilfs2: convert nilfs_mdt_submit_block to use a folio

Saves two calls to compound_head().

Link: https://lkml.kernel.org/r/20231114084436.2755-14-konishi.ryusuke@gmail.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

nilfs2: convert nilfs_mdt_create_block to use a folio

Saves two calls to compound_head().

Link: https://lkml.kernel.org/r/20231114084436.2755-13-konishi.ryusuke@gmail.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

nilfs2: convert to nilfs_clear_folio_dirty()

All callers of nilfs_clear_dirty_page() now have a folio, so rename the
function and pass in the folio. Saves three hidden calls to
compound_head().

Link: https://lkml.kernel.org/r/20231114084436.2755-9-konishi.ryusuke@gmail.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

nilfs2: convert nilfs_mdt_write_page() to use a folio

Convert the incoming page to a folio. Replaces three calls to
compound_head() with one.

Link: https://lkml.kernel.org/r/20231114084436.2755-8-konishi.ryusuke@gmail.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

buffer: remove folio_create_empty_buffers()

With all users converted, remove the old create_empty_buffers() and rename
folio_create_empty_buffers() to create_empty_buffers().

Link: https://lkml.kernel.org/r/20231016201114.1928083-28-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

nilfs2: convert nilfs_mdt_get_frozen_buffer to use a folio

Remove a number of folio->page->folio conversions.

Link: https://lkml.kernel.org/r/20231016201114.1928083-15-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

nilfs2: convert nilfs_mdt_forget_block() to use a folio

Remove a number of folio->page->folio conversions.

Link: https://lkml.kernel.org/r/20231016201114.1928083-14-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

nilfs2: convert nilfs_mdt_freeze_buffer to use a folio

Remove a number of folio->page->folio conversions.

Link: https://lkml.kernel.org/r/20231016201114.1928083-11-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

nilfs2: replace obvious uses of b_page with b_folio

These places just use b_page to get to the buffer's address_space or the
index of the page the buffer is in.

Link: https://lkml.kernel.org/r/20221215214402.3522366-11-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/nilfs2: Use the enum req_op and blk_opf_t types

Improve static type checking by using the enum req_op type for variables
that represent a request operation and the new blk_opf_t type for
variables that represent request flags. Combine the 'mode' and
'mode_flags' arguments of nilfs_btnode_submit_block into a single
argument 'opf'.

Reviewed-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-59-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/buffer: Combine two submit_bh() and ll_rw_block() arguments

Both submit_bh() and ll_rw_block() accept a request operation type and
request flags as their first two arguments. Micro-optimize these two
functions by combining these first two arguments into a single argument.
This patch does not change the behavior of any of the modified code.

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jan Kara <jack@suse.cz>
Acked-by: Song Liu <song@kernel.org> (for the md changes)
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-48-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nilfs2: fix lockdep warnings during disk space reclamation

During disk space reclamation, nilfs2 still emits the following lockdep
warning due to page/folio operations on shadowed page caches that nilfs2
uses to get a snapshot of DAT file in memory:

WARNING: CPU: 0 PID: 2643 at include/linux/backing-dev.h:272 __folio_mark_dirty+0x645/0x670
...
RIP: 0010:__folio_mark_dirty+0x645/0x670
...
Call Trace:
filemap_dirty_folio+0x74/0xd0
__set_page_dirty_nobuffers+0x85/0xb0
nilfs_copy_dirty_pages+0x288/0x510 [nilfs2]
nilfs_mdt_save_to_shadow_map+0x50/0xe0 [nilfs2]
nilfs_clean_segments+0xee/0x5d0 [nilfs2]
nilfs_ioctl_clean_segments.isra.19+0xb08/0xf40 [nilfs2]
nilfs_ioctl+0xc52/0xfb0 [nilfs2]
__x64_sys_ioctl+0x11d/0x170

This fixes the remaining warning by using inode objects to hold those
page caches.

Link: https://lkml.kernel.org/r/1647867427-30498-3-git-send-email-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hao Sun <sunhao.th@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: fix lockdep warnings in page operations for btree nodes

Patch series "nilfs2 lockdep warning fixes".

The first two are to resolve the lockdep warning issue, and the last one
is the accompanying cleanup and low priority.

Based on your comment, this series solves the issue by separating inode
object as needed. Since I was worried about the impact of the object
composition changes, I tested the series carefully not to cause
regressions especially for delicate functions such like disk space
reclamation and snapshots.

This patch (of 3):

If CONFIG_LOCKDEP is enabled, nilfs2 hits lockdep warnings at
inode_to_wb() during page/folio operations for btree nodes:

WARNING: CPU: 0 PID: 6575 at include/linux/backing-dev.h:269 inode_to_wb include/linux/backing-dev.h:269 [inline]
WARNING: CPU: 0 PID: 6575 at include/linux/backing-dev.h:269 folio_account_dirtied mm/page-writeback.c:2460 [inline]
WARNING: CPU: 0 PID: 6575 at include/linux/backing-dev.h:269 __folio_mark_dirty+0xa7c/0xe30 mm/page-writeback.c:2509
Modules linked in:
...
RIP: 0010:inode_to_wb include/linux/backing-dev.h:269 [inline]
RIP: 0010:folio_account_dirtied mm/page-writeback.c:2460 [inline]
RIP: 0010:__folio_mark_dirty+0xa7c/0xe30 mm/page-writeback.c:2509
...
Call Trace:
__set_page_dirty include/linux/pagemap.h:834 [inline]
mark_buffer_dirty+0x4e6/0x650 fs/buffer.c:1145
nilfs_btree_propagate_p fs/nilfs2/btree.c:1889 [inline]
nilfs_btree_propagate+0x4ae/0xea0 fs/nilfs2/btree.c:2085
nilfs_bmap_propagate+0x73/0x170 fs/nilfs2/bmap.c:337
nilfs_collect_dat_data+0x45/0xd0 fs/nilfs2/segment.c:625
nilfs_segctor_apply_buffers+0x14a/0x470 fs/nilfs2/segment.c:1009
nilfs_segctor_scan_file+0x47a/0x700 fs/nilfs2/segment.c:1048
nilfs_segctor_collect_blocks fs/nilfs2/segment.c:1224 [inline]
nilfs_segctor_collect fs/nilfs2/segment.c:1494 [inline]
nilfs_segctor_do_construct+0x14f3/0x6c60 fs/nilfs2/segment.c:2036
nilfs_segctor_construct+0x7a7/0xb30 fs/nilfs2/segment.c:2372
nilfs_segctor_thread_construct fs/nilfs2/segment.c:2480 [inline]
nilfs_segctor_thread+0x3c3/0xf90 fs/nilfs2/segment.c:2563
kthread+0x405/0x4f0 kernel/kthread.c:327
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

This is because nilfs2 uses two page caches for each inode and
inode->i_mapping never points to one of them, the btree node cache.

This causes inode_to_wb(inode) to refer to a different page cache than
the caller page/folio operations such like __folio_start_writeback(),
__folio_end_writeback(), or __folio_mark_dirty() acquired the lock.

This patch resolves the issue by allocating and using an additional
inode to hold the page cache of btree nodes. The inode is attached
one-to-one to the traditional nilfs2 inode if it requires a block
mapping with b-tree. This setup change is in memory only and does not
affect the disk format.

Link: https://lkml.kernel.org/r/1647867427-30498-1-git-send-email-konishi.ryusuke@gmail.com
Link: https://lkml.kernel.org/r/1647867427-30498-2-git-send-email-konishi.ryusuke@gmail.com
Link: https://lore.kernel.org/r/YXrYvIo8YRnAOJCj@casper.infradead.org
Link: https://lore.kernel.org/r/9a20b33d-b38f-b4a2-4742-c1eb5b8e4d6c@redhat.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+0d5b462a6f07447991b3@syzkaller.appspotmail.com
Reported-by: syzbot+34ef28bb2aeb28724aa0@syzkaller.appspotmail.com
Reported-by: Hao Sun <sunhao.th@gmail.com>
Reported-by: David Hildenbrand <david@redhat.com>
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs: Convert __set_page_dirty_buffers to block_dirty_folio

Convert all callers; mostly this is just changing the aops to point
at it, but a few implementations need a little more work.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: Mike Marshall <hubcap@omnibond.com> # orangefs
Tested-by: David Howells <dhowells@redhat.com> # afs

fs: Turn block_invalidatepage into block_invalidate_folio

Remove special-casing of a NULL invalidatepage, since there is no
more block_invalidatepage.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: Mike Marshall <hubcap@omnibond.com> # orangefs
Tested-by: David Howells <dhowells@redhat.com> # afs

nilfs2: remove filenames from file comments

Remove filenames that are not particularly useful in file comments, and
suppress checkpatch warnings

WARNING: It's generally not useful to have the filename in the file

Link: https://lkml.kernel.org/r/1635151862-11547-3-git-send-email-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Qing Wang <wangqing@vivo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: require ->set_page_dirty to be explicitly wired up

Remove the CONFIG_BLOCK default to __set_page_dirty_buffers and just wire
that method up for the missing instances.

[hch@lst.de: ecryptfs: add a ->set_page_dirty cludge]
Link: https://lkml.kernel.org/r/20210624125250.536369-1-hch@lst.de

Link: https://lkml.kernel.org/r/20210614061512.3966143-4-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Tyler Hicks <code@tyhicks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: use a more common logging style

Add macros for nilfs_<level>(sb, fmt, ...) and convert the uses of
'nilfs_msg(sb, KERN_<LEVEL>, ...)' to 'nilfs_<level>(sb, ...)' so nilfs2
uses a logging style more like the typical kernel logging style.

Miscellanea:

o Realign arguments for these uses

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1595860111-3920-4-git-send-email-konishi.ryusuke@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: convert to SPDX license tags

Remove the verbose license text from NILFS2 files and replace them with
SPDX tags. This does not change the license of any of the code.

Link: http://lkml.kernel.org/r/1535624528-5982-1-git-send-email-konishi.ryusuke@lab.ntt.co.jp
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb)

Firstly by applying the following with coccinelle's spatch:

@@ expression SB; @@
-SB->s_flags & MS_RDONLY
+sb_rdonly(SB)

to effect the conversion to sb_rdonly(sb), then by applying:

@@ expression A, SB; @@
(
-(!sb_rdonly(SB)) && A
+!sb_rdonly(SB) && A
|
-A != (sb_rdonly(SB))
+A != sb_rdonly(SB)
|
-A == (sb_rdonly(SB))
+A == sb_rdonly(SB)
|
-!(sb_rdonly(SB))
+!sb_rdonly(SB)
|
-A && (sb_rdonly(SB))
+A && sb_rdonly(SB)
|
-A || (sb_rdonly(SB))
+A || sb_rdonly(SB)
|
-(sb_rdonly(SB)) != A
+sb_rdonly(SB) != A
|
-(sb_rdonly(SB)) == A
+sb_rdonly(SB) == A
|
-(sb_rdonly(SB)) && A
+sb_rdonly(SB) && A
|
-(sb_rdonly(SB)) || A
+sb_rdonly(SB) || A
)

@@ expression A, B, SB; @@
(
-(sb_rdonly(SB)) ? 1 : 0
+sb_rdonly(SB)
|
-(sb_rdonly(SB)) ? A : B
+sb_rdonly(SB) ? A : B
)

to remove left over excess bracketage and finally by applying:

@@ expression A, SB; @@
(
-(A & MS_RDONLY) != sb_rdonly(SB)
+(bool)(A & MS_RDONLY) != sb_rdonly(SB)
|
-(A & MS_RDONLY) == sb_rdonly(SB)
+(bool)(A & MS_RDONLY) == sb_rdonly(SB)
)

to make comparisons against the result of sb_rdonly() (which is a bool)
work correctly.

Signed-off-by: David Howells <dhowells@redhat.com>

fs: add i_blocksize()

Replace all 1 << inode->i_blkbits and (1 << inode->i_blkbits) in fs
branch.

This patch also fixes multiple checkpatch warnings: WARNING: Prefer
'unsigned int' to bare use of 'unsigned'

Thanks to Andrew Morton for suggesting more appropriate function instead
of macro.

[geliangtang@gmail.com: truncate: use i_blocksize()]
Link: http://lkml.kernel.org/r/9c8b2cd83c8f5653805d43debde9fa8817e02fc4.1484895804.git.geliangtang@gmail.com
Link: http://lkml.kernel.org/r/1481319905-10126-1-git-send-email-fabf@skynet.be
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: emit error message when I/O error is detected

When nilfs returned -EIO as an error code, it's not always clear if it
came from the underlying block device or not. This will mend the issue
by having low level I/O routines of nilfs output an error message when
they detected an I/O error.

Link: http://lkml.kernel.org/r/1464875891-5443-7-git-send-email-konishi.ryusuke@lab.ntt.co.jp
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs: have submit_bh users pass in op and flags separately

This has submit_bh users pass in the operation and flags separately,
so submit_bh_wbc can setup the bio op and bi_rw flags on the bio that
is submitted.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

nilfs2: avoid bare use of 'unsigned'

This fixes checkpatch.pl warning "WARNING: Prefer 'unsigned int' to
bare use of 'unsigned'".

Link: http://lkml.kernel.org/r/1462886671-3521-5-git-send-email-konishi.ryusuke@lab.ntt.co.jp
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: move cleanup code of metadata file from inode routines

Refactor nilfs_clear_inode() and nilfs_i_callback() so that cleanup
code or resource deallocation related to metadata file will be moved
out to mdt.c.

Link: http://lkml.kernel.org/r/1461935747-10380-9-git-send-email-konishi.ryusuke@lab.ntt.co.jp
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: get rid of nilfs_mdt_mark_block_dirty()

nilfs_mdt_mark_block_dirty() can be replaced with primary functions
like nilfs_mdt_get_block() and mark_buffer_dirty(), and it's used only
by nilfs_ioctl_mark_blocks_dirty().

This gets rid of the function to simplify the interface of metadata
file.

Link: http://lkml.kernel.org/r/1461935747-10380-8-git-send-email-konishi.ryusuke@lab.ntt.co.jp
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: clean up old e-mail addresses

E-mail addresses of osrg.net domain are no longer available. This
removes them from authorship notices and prevents reporters from being
confused.

Link: http://lkml.kernel.org/r/1461935747-10380-5-git-send-email-konishi.ryusuke@lab.ntt.co.jp
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: remove FSF mailing address from GPL notices

This removes the extra paragraph which mentions FSF address in GPL
notices from source code of nilfs2 and avoids the checkpatch.pl error
related to it.

Link: http://lkml.kernel.org/r/1461935747-10380-4-git-send-email-konishi.ryusuke@lab.ntt.co.jp
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.

This promise never materialized. And unlikely will.

We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE. And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.

Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.

Let's stop pretending that pages in page cache are special. They are
not.

The changes are pretty straight-forward:

- <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

- <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

- PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};

- page_cache_get() -> get_page();

- page_cache_release() -> put_page();

This patch contains automated changes generated with coccinelle using
script below. For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.

The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.

There are few places in the code where coccinelle didn't reach. I'll
fix them manually in a separate patch. Comments and documentation also
will be addressed with the separate patch.

virtual patch

@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT

@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE

@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK

@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)

@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)

@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: add tracepoints for analyzing reading and writing metadata files

This patch adds tracepoints for analyzing requests of reading and writing
metadata files. The tracepoints cover every in-place mdt files (cpfile,
sufile, and datfile).

Example of tracing mdt_insert_new_block():
cp-14635 [000] ...1 30598.199309: nilfs2_mdt_insert_new_block: inode = ffff88022a8d0178 ino = 3 block = 155
cp-14635 [000] ...1 30598.199520: nilfs2_mdt_insert_new_block: inode = ffff88022a8d0178 ino = 3 block = 5
cp-14635 [000] ...1 30598.200828: nilfs2_mdt_insert_new_block: inode = ffff88022a8d0178 ino = 3 block = 253

Signed-off-by: Hitoshi Mitake <mitake.hitoshi@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: TK Kato <TK.Kato@wdc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: add helper to find existent block on metadata file

Add a new metadata file function, nilfs_mdt_find_block(), which finds
an existent block on a metadata file in a given range of blocks. This
function skips continuous hole blocks efficiently by using
nilfs_bmap_seek_key().

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs: remove mapping->backing_dev_info

Now that we never use the backing_dev_info pointer in struct address_space
we can simply remove it and save 4 to 8 bytes in every inode.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Reviewed-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>

nilfs2: fix issue with flush kernel thread after remount in RO mode because of driver's internal error or metadata corruption

The NILFS2 driver remounts itself in RO mode in the case of discovering
metadata corruption (for example, discovering a broken bmap). But
usually, this takes place when there have been file system operations
before remounting in RO mode.

Thereby, NILFS2 driver can be in RO mode with presence of dirty pages in
modified inodes' address spaces. It results in flush kernel thread's
infinite trying to flush dirty pages in RO mode. As a result, it is
possible to see such side effects as: (1) flush kernel thread occupies
50% - 99% of CPU time; (2) system can't be shutdowned without manual
power switch off.

SYMPTOMS:
(1) System log contains error message: "Remounting filesystem read-only".
(2) The flush kernel thread occupies 50% - 99% of CPU time.
(3) The system can't be shutdowned without manual power switch off.

REPRODUCTION PATH:
(1) Create volume group with name "unencrypted" by means of vgcreate utility.
(2) Run script (prepared by Anthony Doggett <Anthony2486@interfaces.org.uk>):

----------------[BEGIN SCRIPT]--------------------
#!/bin/bash

VG=unencrypted
#apt-get install nilfs-tools darcs
lvcreate --size 2G --name ntest $VG
mkfs.nilfs2 -b 1024 -B 8192 /dev/mapper/$VG-ntest
mkdir /var/tmp/n
mkdir /var/tmp/n/ntest
mount /dev/mapper/$VG-ntest /var/tmp/n/ntest
mkdir /var/tmp/n/ntest/thedir
cd /var/tmp/n/ntest/thedir
sleep 2
date
darcs init
sleep 2
dmesg|tail -n 5
date
darcs whatsnew || true
date
sleep 2
dmesg|tail -n 5
----------------[END SCRIPT]--------------------

(3) Try to shutdown the system.

REPRODUCIBILITY: 100%

FIX:

This patch implements checking mount state of NILFS2 driver in
nilfs_writepage(), nilfs_writepages() and nilfs_mdt_write_page()
methods. If it is detected the RO mount state then all dirty pages are
simply discarded with warning messages is written in system log.

[akpm@linux-foundation.org: fix printk warning]
Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Anthony Doggett <Anthony2486@interfaces.org.uk>
Cc: ARAI Shun-ichi <hermes@ceres.dti.ne.jp>
Cc: Piotr Szymaniak <szarpaj@grubelek.pl>
Cc: Zahid Chowdhury <zahid.chowdhury@starsolutions.com>
Cc: Elmer Zhang <freeboy6716@gmail.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: remove the second argument of k[un]map_atomic()

Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Cong Wang <amwang@redhat.com>

nilfs2: use mark_buffer_dirty to mark btnode or meta data dirty

This replaces nilfs_mdt_mark_buffer_dirty and nilfs_btnode_mark_dirty
macros with mark_buffer_dirty and gets rid of nilfs_mark_buffer_dirty,
an own mark buffer dirty function.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: always set back pointer to host inode in mapping->host

In the current nilfs, page cache for btree nodes and meta data files
do not set a valid back pointer to the host inode in mapping->host.

This will change it so that every address space in nilfs uses
mapping->host to hold its host inode.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

block: remove per-queue plugging

Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

mm: prevent concurrent unmap_mapping_range() on the same inode

Michael Leun reported that running parallel opens on a fuse filesystem
can trigger a "kernel BUG at mm/truncate.c:475"

Gurudas Pai reported the same bug on NFS.

The reason is, unmap_mapping_range() is not prepared for more than
one concurrent invocation per inode. For example:

thread1: going through a big range, stops in the middle of a vma and
stores the restart address in vm_truncate_count.

thread2: comes in with a small (e.g. single page) unmap request on
the same vma, somewhere before restart_address, finds that the
vma was already unmapped up to the restart address and happily
returns without doing anything.

Another scenario would be two big unmap requests, both having to
restart the unmapping and each one setting vm_truncate_count to its
own value. This could go on forever without any of them being able to
finish.

Truncate and hole punching already serialize with i_mutex. Other
callers of unmap_mapping_range() do not, and it's difficult to get
i_mutex protection for all callers. In particular ->d_revalidate(),
which calls invalidate_inode_pages2_range() in fuse, may be called
with or without i_mutex.

This patch adds a new mutex to 'struct address_space' to prevent
running multiple concurrent unmap_mapping_range() on the same mapping.

[ We'll hopefully get rid of all this with the upcoming mm
preemptibility series by Peter Zijlstra, the "mm: Remove i_mmap_mutex
lockbreak" patch in particular. But that is for 2.6.39 ]

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reported-by: Michael Leun <lkml20101129@newton.leun.net>
Reported-by: Gurudas Pai <gurudas.pai@oracle.com>
Tested-by: Gurudas Pai <gurudas.pai@oracle.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: simplify nilfs_mdt_freeze_buffer

nilfs_page_get_nth_block() function used in nilfs_mdt_freeze_buffer()
always returns a valid buffer head, so its validity check can be
removed.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: call nilfs_error inside bmap routines

Some functions using nilfs bmap routines can wrongly return invalid
argument error (i.e. -EINVAL) that bmap returns as an internal code
for btree corruption.

This fixes the issue by catching and converting the internal EINVAL to
EIO and calling nilfs_error function inside bmap routines.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: get rid of bdi from nilfs object

Nilfs now can use sb->s_bdi to get backing_dev_info, so we use it
instead of ns_bdi on the nilfs object and remove ns_bdi.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: remove own inode allocator and destructor for metadata files

This finally removes own inode allocator and destructor functions for
metadata files. Several routines, nilfs_mdt_new(),
nilfs_mdt_new_common(), nilfs_mdt_clear(), nilfs_mdt_destroy(), and
nilfs_alloc_inode_common() will be gone.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: get rid of back pointer to writable sb instance

Nilfs object holds a back pointer to a writable super block instance
in nilfs->ns_writer, and this became eliminable since sb is now made
per device and all inodes have a valid pointer to it.

This deletes the ns_writer pointer and a reader/writer semaphore
protecting it.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: get rid of mi_nilfs back pointer to nilfs object

This removes a back pointer to nilfs object from nilfs_mdt_info
structure that is attached to metadata files.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: use iget for all metadata files

This makes use of iget5_locked to allocate or get inode for metadata
files to stop using own inode allocator.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: get rid of GCDAT inode

This applies prepared rollback function and redirect function of
metadata file to DAT file, and eliminates GCDAT inode.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: add routines to redirect access to buffers of DAT file

During garbage collection (GC), DAT file, which converts virtual block
number to real block number, may return disk block number that is not
yet written to the device.

To avoid access to unwritten blocks, the current implementation stores
changes to the caches of GCDAT during GC and atomically commit the
changes into the DAT file after they are written to the device.

This patch, instead, adds a function that makes a copy of specified
buffer and stores it in nilfs_shadow_map, and a function to get the
backup copy as needed (nilfs_mdt_freeze_buffer and
nilfs_mdt_get_frozen_buffer respectively).

Before DAT changes block number in an entry block, it makes a copy and
redirect access to the buffer so that address conversion function
(i.e. nilfs_dat_translate) refers to the old address saved in the
copy.

This patch gives requisites for such redirection.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: add routines to roll back state of DAT file

This adds optional function to metadata files which makes a copy of
bmap, page caches, and b-tree node cache, and rolls back to the copy
as needed.

This enhancement is intended to displace gcdat inode that provides a
similar function in a different way.

In this patch, nilfs_shadow_map structure is added to store a copy of
the foregoing states. nilfs_mdt_setup_shadow_map relates this
structure to a metadata file. And, nilfs_mdt_save_to_shadow_map() and
nilfs_mdt_restore_from_shadow_map() provides save and restore
functions respectively. Finally, nilfs_mdt_clear_shadow_map() clears
states of nilfs_shadow_map.

The copy of b-tree node cache and page cache is made by duplicating
only dirty pages into corresponding caches in nilfs_shadow_map. Their
restoration is done by clearing dirty pages from original caches and
by copying dirty pages back from nilfs_shadow_map.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: separate initializer of metadata file inode

This separates a part of initialization code of metadata file inode,
and makes it available from the nilfs iget function that a later patch
will add to.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: allow nilfs_destroy_inode to destroy metadata file inodes

The current nilfs_destroy_inode() doesn't handle metadata file inodes
including gc inodes (dummy inodes used for garbage collection).

This allows nilfs_destroy_inode() to destroy inodes of metadata files.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: get rid of nilfs_bmap_union

This removes nilfs_bmap_union and finally unifies three structures and
the union in bmap/btree code into one.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

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>

nilfs2: add cache framework for persistent object allocator

This adds setup and cleanup routines of the persistent object
allocator cache.

According to ftrace analyses, accessing buffers of the DAT file
suffers indispensable overhead many times. To mitigate the overhead,
This introduce cache framework for the persistent object allocator
(palloc) which the DAT file and ifile are using.

struct nilfs_palloc_cache represents the cache object per metadata
file using palloc.

The cache is initialized through nilfs_palloc_setup_cache() and
destroyed by nilfs_palloc_destroy_cache(); callers of the former
function will be added to individual allocators of DAT and ifile on
successive patches.

nilfs_palloc_destroy_cache() will be called from nilfs_mdt_destroy()
if the cache is attached to a metadata file. A companion function
nilfs_palloc_clear_cache() is provided to allow releasing buffer head
references independently with the cleanup task. This adjunctive
function will be used before invalidating pages of metadata file with
the cache.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: avoid readahead on metadata file for create mode

This turns off readhead action of metadata file if nilfs_mdt_get_block
function was called with a create flag.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: hide nilfs_mdt_clear calls in nilfs_mdt_destroy

This will hide a function call of nilfs_mdt_clear() in
nilfs_mdt_destroy().

This ensures nilfs_mdt_destroy() to do cleanup jobs included in
nilfs_mdt_clear().

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: add size option of private object to metadata file allocator

This adds an optional "object size" argument to nilfs_mdt_new_common()
function; the argument specifies the size of private object attached
to a newly allocated metadata file inode.

This will afford space to keep local variables for meta data files.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

const: constify remaining file_operations

[akpm@linux-foundation.org: fix KVM]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

const: mark remaining inode_operations as const

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

const: mark remaining address_space_operations const

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: convert nilfs_bmap_lookup to an inline function

The nilfs_bmap_lookup() is now a wrapper function of
nilfs_bmap_lookup_at_level().

This moves the nilfs_bmap_lookup() to a header file converting it to
an inline function and gives an opportunity for optimization.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: remove individual gfp constants for each metadata file

This gets rid of NILFS_CPFILE_GFP, NILFS_SUFILE_GFP, NILFS_DAT_GFP,
and NILFS_IFILE_GFP. All of these constants refer to NILFS_MDT_GFP,
and can be removed.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: always lookup disk block address before reading metadata block

The current metadata file code skips disk address lookup for its data
block if the buffer has a mapped flag.

This has a potential risk to cause read request to be performed
against the stale block address that GC moved, and it may lead to meta
data corruption. The mapped flag is safe if the buffer has an
uptodate flag, otherwise it may prevent necessary update of disk
address in the next read.

This will avoid the potential problem by ensuring disk address lookup
before reading metadata block even for buffers with the mapped flag.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: use semaphore to protect pointer to a writable FS-instance

will get rid of nilfs_get_writer() and nilfs_put_writer() pair used to
retain a writable FS-instance for a period.

The pair functions were making up some kind of recursive lock with a
mutex, but they became overkill since the commit
201913ed746c7724a40d33ee5a0b6a1fd2ef3193. Furthermore, they caused
the following lockdep warning because the mutex can be released by a
task which didn't lock it:

=====================================
[ BUG: bad unlock balance detected! ]
-------------------------------------
kswapd0/422 is trying to release lock (&nilfs->ns_writer_mutex) at:
[<c1359ff5>] mutex_unlock+0x8/0xa
but there are no more locks to release!

other info that might help us debug this:
no locks held by kswapd0/422.

stack backtrace:
Pid: 422, comm: kswapd0 Not tainted 2.6.31-rc4-nilfs #51
Call Trace:
[<c1358f97>] ? printk+0xf/0x18
[<c104fea7>] print_unlock_inbalance_bug+0xcc/0xd7
[<c11578de>] ? prop_put_global+0x3/0x35
[<c1050195>] lock_release+0xed/0x1dc
[<c1359ff5>] ? mutex_unlock+0x8/0xa
[<c1359f83>] __mutex_unlock_slowpath+0xaf/0x119
[<c1359ff5>] mutex_unlock+0x8/0xa
[<d1284add>] nilfs_mdt_write_page+0xd8/0xe1 [nilfs2]
[<c1092653>] shrink_page_list+0x379/0x68d
[<c109171b>] ? isolate_pages_global+0xb4/0x18c
[<c1092bd2>] shrink_list+0x26b/0x54b
[<c10930be>] shrink_zone+0x20c/0x2a2
[<c10936b7>] kswapd+0x407/0x591
[<c1091667>] ? isolate_pages_global+0x0/0x18c
[<c1040603>] ? autoremove_wake_function+0x0/0x33
[<c10932b0>] ? kswapd+0x0/0x591
[<c104033b>] kthread+0x69/0x6e
[<c10402d2>] ? kthread+0x0/0x6e
[<c1003e33>] kernel_thread_helper+0x7/0x1a

This patch uses a reader/writer semaphore instead of the own lock and
kills this warning.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: fix missing unlock in error path of nilfs_mdt_write_page

This adds a missing unlock of nilfs->ns_writer_mutex in
nilfs_mdt_write_page() function.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: add sync_page method to page caches of meta data

This applies block_sync_page() function to the sync_page method of
page caches for meta data files, gc page caches, and btree node
buffers. This is a companion patch of ("nilfs2: enable sync_page
mothod") which applied the function for data pages.

This allows lock_page() for those meta data to unplug pending bio
requests.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: use device's backing_dev_info for btree node caches

Previously, default_backing_dev_info was used for the mapping of btree
node caches. This uses device dependent backing_dev_info to allow
detailed control of the device for the btree node pages.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: ensure to clear dirty state when deleting metadata file block

This would fix the following failure during GC:

nilfs_cpfile_delete_checkpoints: cannot delete block
NILFS: GC failed during preparation: cannot delete checkpoints: err=-2

The problem was caused by a break in state consistency between page
cache and btree; the above block was removed from the btree but the
page buffering the block was remaining in the page cache in dirty
state.

This resolves the inconsistency by ensuring to clear dirty state of
the page buffering the deleted block.

Reported-by: David Arendt <admin@prnet.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: fix circular locking dependency of writer mutex

This fixes the following circular locking dependency problem:

=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.30-rc3 #5
-------------------------------------------------------
segctord/3895 is trying to acquire lock:
(&nilfs->ns_writer_mutex){+.+...}, at: [<d0d02172>]
nilfs_mdt_get_block+0x89/0x20f [nilfs2]

but task is already holding lock:
(&bmap->b_sem){++++..}, at: [<d0d02d99>]
nilfs_bmap_propagate+0x14/0x2e [nilfs2]

which lock already depends on the new lock.

The bugfix is done by replacing call sites of nilfs_get_writer() which
are never called from read-only context with direct dereferencing of
pointer to a writable FS-instance.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: replace BUG_ON and BUG calls triggerable from ioctl

Pekka Enberg advised me:
> It would be nice if BUG(), BUG_ON(), and panic() calls would be
> converted to proper error handling using WARN_ON() calls. The BUG()
> call in nilfs_cpfile_delete_checkpoints(), for example, looks to be
> triggerable from user-space via the ioctl() system call.

This will follow the comment and keep them to a minimum.

Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: avoid double error caused by nilfs_transaction_end

Pekka Enberg pointed out that double error handlings found after
nilfs_transaction_end() can be avoided by separating abort operation:

OK, I don't understand this. The only way nilfs_transaction_end() can
fail is if we have NILFS_TI_SYNC set and we fail to construct the
segment. But why do we want to construct a segment if we don't commit?

I guess what I'm asking is why don't we have a separate
nilfs_transaction_abort() function that can't fail for the erroneous
case to avoid this double error value tracking thing?

This does the separation and renames nilfs_transaction_end() to
nilfs_transaction_commit() for clarification.

Since, some calls of these functions were used just for exclusion control
against the segment constructor, they are replaced with semaphore
operations.

Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: meta data file

This adds the meta data file, which serves common buffer functions to the
DAT, sufile, cpfile, ifile, and so forth.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>