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| author |   Christoph Hellwig <hch@lst.de> | 2007-09-10 20:02:30 -0400 |
|---|---|---|
| committer |   David Woodhouse <dwmw2@hera.kernel.org> | 2007-09-10 20:02:30 -0400 |
| commit | d396c6f554d182b7bce4e2bb2acb47f80430c05f (patch) | |
| tree | 2bc7b567310474ed4562d4e1246efd69a868f8cd /fs/btrfs/extent_map.c | |
| parent | Btrfs: [PATCH] extent_map: fix locking for bio completion (diff) | |
| download | linux-dev-d396c6f554d182b7bce4e2bb2acb47f80430c05f.tar.xz linux-dev-d396c6f554d182b7bce4e2bb2acb47f80430c05f.zip | |
Btrfs: [PATCH] extent_map: provide generic bmap
generic_bmap is completely trivial, while the extent to bh mapping in
btrfs is rather complex. So provide a extent_bmap instead that takes
a get_extent callback and can be used by filesystem using the extent_map
code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/extent_map.c')
| -rw-r--r-- | fs/btrfs/extent_map.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index 3021564ac62c..ff2b1dd25bf9 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -1816,3 +1816,22 @@ int try_release_extent_mapping(struct extent_map_tree *tree, struct page *page) } EXPORT_SYMBOL(try_release_extent_mapping); +sector_t extent_bmap(struct address_space *mapping, sector_t iblock, + get_extent_t *get_extent) +{ + struct inode *inode = mapping->host; + u64 start = iblock << inode->i_blkbits; + u64 end = start + (1 << inode->i_blkbits) - 1; + struct extent_map *em; + + em = get_extent(inode, NULL, 0, start, end, 0); + if (!em || IS_ERR(em)) + return 0; + + // XXX(hch): block 0 is valid in some cases, e.g. XFS RT device + if (em->block_start == EXTENT_MAP_INLINE || + em->block_start == 0) + return 0; + + return (em->block_start + start - em->start) >> inode->i_blkbits; +} |