aboutsummaryrefslogtreecommitdiffstats
path: root/fs/ext4/extents.c
diff options
context:
space:
mode:
authorLeonard Michlmayr <leonard.michlmayr@gmail.com>2010-03-04 17:07:28 -0500
committerTheodore Ts'o <tytso@mit.edu>2010-03-04 17:07:28 -0500
commitaca92ff6f57c000d1b4523e383c8bd6b8269b8b1 (patch)
treec810b72c091b8bf596a21ee4d56c830b9d0c4c50 /fs/ext4/extents.c
parent9aaab0589baa61d637a52badddbff2d74f35a955 (diff)
ext4: correctly calculate number of blocks for fiemap
ext4_fiemap() rounds the length of the requested range down to blocksize, which is is not the true number of blocks that cover the requested region. This problem is especially impressive if the user requests only the first byte of a file: not a single extent will be reported. We fix this by calculating the last block of the region and then subtract to find the number of blocks in the extents. Signed-off-by: Leonard Michlmayr <leonard.michlmayr@gmail.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/extents.c')
-rw-r--r--fs/ext4/extents.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index bd808915ad2f..7d54850f7136 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3768,7 +3768,6 @@ int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
3768 __u64 start, __u64 len) 3768 __u64 start, __u64 len)
3769{ 3769{
3770 ext4_lblk_t start_blk; 3770 ext4_lblk_t start_blk;
3771 ext4_lblk_t len_blks;
3772 int error = 0; 3771 int error = 0;
3773 3772
3774 /* fallback to generic here if not in extents fmt */ 3773 /* fallback to generic here if not in extents fmt */
@@ -3782,8 +3781,14 @@ int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
3782 if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) { 3781 if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
3783 error = ext4_xattr_fiemap(inode, fieinfo); 3782 error = ext4_xattr_fiemap(inode, fieinfo);
3784 } else { 3783 } else {
3784 ext4_lblk_t len_blks;
3785 __u64 last_blk;
3786
3785 start_blk = start >> inode->i_sb->s_blocksize_bits; 3787 start_blk = start >> inode->i_sb->s_blocksize_bits;
3786 len_blks = len >> inode->i_sb->s_blocksize_bits; 3788 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
3789 if (last_blk >= EXT_MAX_BLOCK)
3790 last_blk = EXT_MAX_BLOCK-1;
3791 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
3787 3792
3788 /* 3793 /*
3789 * Walk the extent tree gathering extent information. 3794 * Walk the extent tree gathering extent information.