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Btrfs: Add fallocate support v2

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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>
This commit is contained in:
Yan Zheng
2008-10-30 14:25:28 -04:00
committed by Chris Mason
parent 80ff385665
commit d899e05215
10 changed files with 563 additions and 117 deletions
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12
fs/btrfs/extent_io.c
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@@ -2015,6 +2015,8 @@ printk("2bad mapping end %Lu cur %Lu\n", end, cur);
}
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 @@ sector_t extent_bmap(struct address_space *mapping, sector_t iblock,
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;