fs/btrfs/inode.c

366  * BTRFS_ILOCK_MMAP - acquire a write lock on the i_mmap_lock
855 	 * finishes, delaying the write of other range.
887 	/* If this is a small write inside eof, kick off a defrag */
902  * work queue to write the uncompressed bytes.  This makes sure that both
1411 			 * allocation.  Otherwise ask the caller to write out
1739  * Run the delalloc range from start to end, and write back any dirty pages
1776 	 * If EXTENT_NORESERVE is set it means that when the buffered write was
1792 	 *    buffered write time, the bytes_may_use counter is incremented);
1983  * If no cow copies or snapshots exist, we write directly to the existing
2872  * the delalloc bit and make it safe to write the page.
3236 		 * Drop extent maps for the part of the extent we didn't write.
3257 		 * truncated case if we didn't write out the extent at all.
4700  * Read, zero a chunk and write a block.
6085  * ENOSPC for updating the inode in the case of file write and mmap writes.
7081  * Check if we can do nocow write into the range [@offset, @offset + @len)
7084  * @len:	The length to write, will be updated to the nocow writeable
7093  * >0	and update @len if we can do nocow write
7094  *  0	if we can't do nocow write
7229 		 * invalidate needs to happen so that reads after a write do not
7247 			 * found is for a buffered write, we can not wait for it
7254 			 * concurrent write against that previous extent map's
7307 	 * Only PREALLOC writes (NOCOW write into preallocated range) can
7338 		 * Encoded write can make us to refer to part of the
7464 		 * range and we can't do a NOCOW write, then we have to fail.
7524 	const bool write = !!(flags & IOMAP_WRITE);
7541 	if (!write && (flags & IOMAP_NOWAIT) && length > PAGE_SIZE)
7548 	if (!write)
7595 	 * NOCOW write.
7597 	if (write && !(flags & IOMAP_NOWAIT)) {
7611 	 * NOWAIT read/write and we need to block.
7685 	if (write) {
7733 	    ((em->flags & EXTENT_FLAG_PREALLOC) && !write)) {
7767 	const bool write = !!(flags & IOMAP_WRITE);
7770 	if (!write && (iomap->type == IOMAP_HOLE)) {
7780 		if (write)
7788 	if (write) {
7793 	if (write)
7844 	 * Check if we are doing a partial write.  If we are, we need to split
7929 	 * possible a new write may have happened in between those two steps.
8359 	 * So if we truncate and then write and fsync we normally would just
8360 	 * write the extents that changed, which is a problem if we need to
8361 	 * first truncate that entire inode.  So set this flag so we write out
9883 		 * write is observed before the load of status in
10230 	 * The extent must end on a sector boundary. However, we allow a write
10564 		btrfs_warn(fs_info, "swapfile must not be copy-on-write");
10591 	 * completes before the first write into the swap file after it is
10592 	 * activated, than that write would fallback to COW.
10673 				   "swapfile must not be copy-on-write");