From 1506fcc8189cdd4b95e06df7845a09f18b4526a6 Mon Sep 17 00:00:00 2001 From: Yehuda Sadeh Date: Wed, 21 Jan 2009 14:39:14 -0500 Subject: Btrfs: fiemap support Now that bmap support is gone, this is the only way to get extent mappings for userland. These are still not valid for IO, but they can tell us if a file has holes or how much fragmentation there is. Signed-off-by: Yehuda Sadeh --- fs/btrfs/extent_io.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) (limited to 'fs/btrfs/extent_io.c') diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index c9446d4840ed..a3b0676403f7 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -2854,6 +2854,98 @@ out: return sector; } +int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, + __u64 start, __u64 len, get_extent_t *get_extent) +{ + int ret; + u64 off = start; + u64 max = start + len; + u32 flags = 0; + u64 disko = 0; + struct extent_map *em = NULL; + int end = 0; + u64 em_start = 0, em_len = 0; + unsigned long emflags; + ret = 0; + + if (len == 0) + return -EINVAL; + + lock_extent(&BTRFS_I(inode)->io_tree, start, start + len, + GFP_NOFS); + em = get_extent(inode, NULL, 0, off, max - off, 0); + if (!em) + goto out; + if (IS_ERR(em)) { + ret = PTR_ERR(em); + goto out; + } + while (!end) { + off = em->start + em->len; + if (off >= max) + end = 1; + + em_start = em->start; + em_len = em->len; + + disko = 0; + flags = 0; + + switch (em->block_start) { + case EXTENT_MAP_LAST_BYTE: + end = 1; + flags |= FIEMAP_EXTENT_LAST; + break; + case EXTENT_MAP_HOLE: + flags |= FIEMAP_EXTENT_UNWRITTEN; + break; + case EXTENT_MAP_INLINE: + flags |= (FIEMAP_EXTENT_DATA_INLINE | + FIEMAP_EXTENT_NOT_ALIGNED); + break; + case EXTENT_MAP_DELALLOC: + flags |= (FIEMAP_EXTENT_DELALLOC | + FIEMAP_EXTENT_UNKNOWN); + break; + default: + disko = em->block_start; + break; + } + if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) + flags |= FIEMAP_EXTENT_ENCODED; + + emflags = em->flags; + free_extent_map(em); + em = NULL; + + if (!end) { + em = get_extent(inode, NULL, 0, off, max - off, 0); + if (!em) + goto out; + if (IS_ERR(em)) { + ret = PTR_ERR(em); + goto out; + } + emflags = em->flags; + } + if (test_bit(EXTENT_FLAG_VACANCY, &emflags)) { + flags |= FIEMAP_EXTENT_LAST; + end = 1; + } + + ret = fiemap_fill_next_extent(fieinfo, em_start, disko, + em_len, flags); + if (ret) + goto out_free; + } +out_free: + free_extent_map(em); +out: + unlock_extent(&BTRFS_I(inode)->io_tree, start, start + len, + GFP_NOFS); + return ret; +} + static inline struct page *extent_buffer_page(struct extent_buffer *eb, unsigned long i) { -- cgit v1.2.1