We need such a sanity check for wrong start, otherwise, even with
a wrong start that's larger than file size, we can end up not only
changing inode's force compress flag but also FS's incompat flags.
Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
---
fs/btrfs/ioctl.c | 11 +++++++----
1 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 69cd80d..262d9db 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1152,8 +1152,11 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
u64 new_align = ~((u64)128 * 1024 - 1);
struct page **pages = NULL;
- if (extent_thresh == 0)
- extent_thresh = 256 * 1024;
+ if (isize == 0)
+ return 0;
+
+ if (range->start >= isize)
+ return -EINVAL;
if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS) {
if (range->compress_type > BTRFS_COMPRESS_TYPES)
@@ -1162,8 +1165,8 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
compress_type = range->compress_type;
}
- if (isize == 0)
- return 0;
+ if (extent_thresh == 0)
+ extent_thresh = 256 * 1024;
/*
* if we were not given a file, allocate a readahead
--
1.7.7
--
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