Message ID | 20110522235625.GC10009@thunk.org |
---|---|
State | Accepted, archived |
Headers | show |
Hi Ted, On Sun, May 22, 2011 at 4:56 PM, Ted Ts'o <tytso@mit.edu> wrote: > Here's a cleaner way of fixing the problem. vmtruncate() is now > deprecated, so I'm using truncate_setsize() instead; in addition, I > avoid calling ext4_truncate() twice in the case where EOFBLOCKS_FL. > Since ext4_truncate() is a very heavyweight function, which requires > manipulating the orphan list and taking i_data_sem, avoiding a double > call of ext4_truncate() is a big win. > > - Ted > > commit bb5eabd2de1e9dfdeeac822174fba17f2d2a7f2b > Author: Theodore Ts'o <tytso@mit.edu> > Date: Sun May 22 19:45:01 2011 -0400 > > ext4: use truncate_setsize() unconditionally > > 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@mit.edu> > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index df3fb20..4ca8411 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 +5397,13 @@ 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); > + attr->ia_size != i_size_read(inode)) { > + truncate_setsize(inode, attr->ia_size); > + ext4_truncate(inode); > + } I think your patch doesn't cover the case when we fallocate with KEEP_SIZE a 12k file, write 4k, and then truncate the file to 4k. In this case, attr->ia_size is equal to i_size but we still want to free any allocated but unwritten blocks during truncate. Jiaying > > if (!rc) { > setattr_copy(inode, attr); > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index df3fb20..4ca8411 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 +5397,13 @@ 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); + attr->ia_size != i_size_read(inode)) { + truncate_setsize(inode, attr->ia_size); + ext4_truncate(inode); + } if (!rc) { setattr_copy(inode, attr);
Here's a cleaner way of fixing the problem. vmtruncate() is now deprecated, so I'm using truncate_setsize() instead; in addition, I avoid calling ext4_truncate() twice in the case where EOFBLOCKS_FL. Since ext4_truncate() is a very heavyweight function, which requires manipulating the orphan list and taking i_data_sem, avoiding a double call of ext4_truncate() is a big win. - Ted commit bb5eabd2de1e9dfdeeac822174fba17f2d2a7f2b Author: Theodore Ts'o <tytso@mit.edu> Date: Sun May 22 19:45:01 2011 -0400 ext4: use truncate_setsize() unconditionally 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@mit.edu> -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html