Hi Andreas and Andi,
Thanks for your comments.
On 09/18/2011 09:46 AM, Andi Kleen wrote:
>>> with an additional improvement if the offset is larger or equal to the
>>> file size, return -ENXIO in directly:
>>>
>>> if (offset >= inode->i_size) {
>>> mutex_unlock(&inode->i_mutex);
>>> return -ENXIO;
>>> }
>>
>> Except that is wrong, because it would then be impossible to write sparse files.
Per my tryout, except that, if the offset >= source file size, call
lseek(fd, offset, SEEK_DATA/SEEK_HOLE) against Btrfs will always return
the total file size rather than -ENXIO. however, our desired result it
-ENXIO in this case, Am I right?
>
> And also i_size must be always read with i_size_read()
Thanks for pointing this out!
Would you please kindly review the revised as below?
Signed-off-by: Jie Liu <jeff.liu@xxxxxxxxxx>
---
fs/btrfs/file.c | 9 +++++++--
1 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index e7872e4..40c1ef3 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1813,6 +1813,11 @@ static loff_t btrfs_file_llseek(struct file
*file, loff_t offset, int origin)
goto out;
case SEEK_DATA:
case SEEK_HOLE:
+ if (offset >= i_size_read(inode)) {
+ mutex_unlock(&inode->i_mutex);
+ return -ENXIO;
+ }
+
ret = find_desired_extent(inode, &offset, origin);
if (ret) {
mutex_unlock(&inode->i_mutex);
@@ -1821,11 +1826,11 @@ static loff_t btrfs_file_llseek(struct file
*file, loff_t offset, int origin)
}
if (offset < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET)) {
- ret = -EINVAL;
+ offset = -EINVAL;
goto out;
}
if (offset > inode->i_sb->s_maxbytes) {
- ret = -EINVAL;
+ offset = -EINVAL;
goto out;
}
--
1.7.4.1
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