tmpfs: truncate prealloc blocks past i_size
One of the rocksdb people noticed that when you do something like this fallocate(fd, FALLOC_FL_KEEP_SIZE, 0, 10M) pwrite(fd, buf, 5M, 0) ftruncate(5M) on tmpfs, the file would still take up 10M: which led to super fun issues because we were getting ENOSPC before we thought we should be getting ENOSPC. This patch fixes the problem, and mirrors what all the other fs'es do (and was agreed to be the correct behaviour at LSF). I tested it locally to make sure it worked properly with the following xfs_io -f -c "falloc -k 0 10M" -c "pwrite 0 5M" -c "truncate 5M" file Without the patch we have "Blocks: 20480", with the patch we have the correct value of "Blocks: 10240". Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
parent
c435a39057
commit
afa2db2fb6
|
@ -569,7 +569,7 @@ static int shmem_setattr(struct dentry *dentry, struct iattr *attr)
|
||||||
i_size_write(inode, newsize);
|
i_size_write(inode, newsize);
|
||||||
inode->i_ctime = inode->i_mtime = CURRENT_TIME;
|
inode->i_ctime = inode->i_mtime = CURRENT_TIME;
|
||||||
}
|
}
|
||||||
if (newsize < oldsize) {
|
if (newsize <= oldsize) {
|
||||||
loff_t holebegin = round_up(newsize, PAGE_SIZE);
|
loff_t holebegin = round_up(newsize, PAGE_SIZE);
|
||||||
unmap_mapping_range(inode->i_mapping, holebegin, 0, 1);
|
unmap_mapping_range(inode->i_mapping, holebegin, 0, 1);
|
||||||
shmem_truncate_range(inode, newsize, (loff_t)-1);
|
shmem_truncate_range(inode, newsize, (loff_t)-1);
|
||||||
|
|
Loading…
Reference in New Issue