Btrfs: Add fallocate support v2
This patch updates btrfs-progs for fallocate support.
fallocate is a little different in Btrfs because we need to tell the
COW system that a given preallocated extent doesn't need to be
cow'd as long as there are no snapshots of it. This leverages the
-o nodatacow checks.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 65a0583..eb3c12e 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2015,6 +2015,8 @@
}
bdev = em->bdev;
block_start = em->block_start;
+ if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
+ block_start = EXTENT_MAP_HOLE;
free_extent_map(em);
em = NULL;
@@ -2769,14 +2771,18 @@
struct inode *inode = mapping->host;
u64 start = iblock << inode->i_blkbits;
sector_t sector = 0;
+ size_t blksize = (1 << inode->i_blkbits);
struct extent_map *em;
- em = get_extent(inode, NULL, 0, start, (1 << inode->i_blkbits), 0);
+ lock_extent(&BTRFS_I(inode)->io_tree, start, start + blksize - 1,
+ GFP_NOFS);
+ em = get_extent(inode, NULL, 0, start, blksize, 0);
+ unlock_extent(&BTRFS_I(inode)->io_tree, start, start + blksize - 1,
+ GFP_NOFS);
if (!em || IS_ERR(em))
return 0;
- if (em->block_start == EXTENT_MAP_INLINE ||
- em->block_start == EXTENT_MAP_HOLE)
+ if (em->block_start > EXTENT_MAP_LAST_BYTE)
goto out;
sector = (em->block_start + start - em->start) >> inode->i_blkbits;