In commit c8d46e41 (ext4: Add flag to files with blocks intentionally
past EOF), if the EOFBLOCKS_FL flag is set, we call ext4_truncate()
before calling vmtruncate(). This caused any allocated but unwritten
blocks created by calling fallocate() with the FALLOC_FL_KEEP_SIZE
flag to be dropped. This was done to make to make sure that
EOFBLOCKS_FL would not be cleared while still leaving blocks past
i_size allocated. This was not necessary, since ext4_truncate()
guarantees that blocks past i_size will be dropped, even in the case
where truncate() has increased i_size before calling ext4_truncate().
So fix this by removing the EOFBLOCKS_FL special case treatment in
ext4_setattr(). In addition, use truncate_setsize() followed by a
call to ext4_truncate() instead of using vmtruncate(). This is more
efficient since it skips the call to inode_newsize_ok(), which has
been checked already by inode_change_ok(). This is also in a win in
the case where EOFBLOCKS_FL is set since it avoids calling
ext4_truncate() twice.
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
---
Jiayingz pointed out that in the case where we fallocate 12k, write 4k, and
then truncate to 4k, we should discard the excess fallocate'd blocks. So if
attr->ia_size == inode.i_size, we can skip the truncate_setsize() call, but
if the EOFBLOCKS_FL flag is set, we should still call ext4_truncate().
fs/ext4/inode.c | 16 ++++++++--------
1 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index df3fb20..2e95819 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5363,8 +5363,7 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
if (S_ISREG(inode->i_mode) &&
attr->ia_valid & ATTR_SIZE &&
- (attr->ia_size < inode->i_size ||
- (ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS)))) {
+ (attr->ia_size < inode->i_size)) {
handle_t *handle;
handle = ext4_journal_start(inode, 3);
@@ -5398,14 +5397,15 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
goto err_out;
}
}
- /* ext4_truncate will clear the flag */
- if ((ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS)))
- ext4_truncate(inode);
}
- if ((attr->ia_valid & ATTR_SIZE) &&
- attr->ia_size != i_size_read(inode))
- rc = vmtruncate(inode, attr->ia_size);
+ if (attr->ia_valid & ATTR_SIZE) {
+ if (attr->ia_size != i_size_read(inode)) {
+ truncate_setsize(inode, attr->ia_size);
+ ext4_truncate(inode);
+ } else if (ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
+ ext4_truncate(inode);
+ }
if (!rc) {
setattr_copy(inode, attr);
--
1.7.3.1
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