3.16.83-rc1 review patch. If anyone has any objections, please let me know.
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From: Jan Kara jack@suse.com
commit 011278485ecc3cd2a3954b5d4c73101d919bf1fa upstream.
When doing delayed allocation, update of on-disk inode size is postponed until IO submission time. However hole punch or zero range fallocate calls can end up discarding the tail page cache page and thus on-disk inode size would never be properly updated.
Make sure the on-disk inode size is updated before truncating page cache.
Signed-off-by: Jan Kara jack@suse.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Ben Hutchings ben@decadent.org.uk --- fs/ext4/ext4.h | 3 +++ fs/ext4/extents.c | 5 +++++ fs/ext4/inode.c | 35 ++++++++++++++++++++++++++++++++++- 3 files changed, 42 insertions(+), 1 deletion(-)
--- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2560,6 +2560,9 @@ static inline int ext4_update_inode_size return changed; }
+int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset, + loff_t len); + struct ext4_group_info { unsigned long bb_state; struct rb_root bb_free_root; --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -4856,6 +4856,11 @@ static long ext4_zero_range(struct file * released from page cache. */ down_write(&EXT4_I(inode)->i_mmap_sem); + ret = ext4_update_disksize_before_punch(inode, offset, len); + if (ret) { + up_write(&EXT4_I(inode)->i_mmap_sem); + goto out_dio; + } /* Now release the pages and zero block aligned part of pages */ truncate_pagecache_range(inode, start, end - 1); inode->i_mtime = inode->i_ctime = ext4_current_time(inode); --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3652,6 +3652,35 @@ int ext4_can_truncate(struct inode *inod }
/* + * We have to make sure i_disksize gets properly updated before we truncate + * page cache due to hole punching or zero range. Otherwise i_disksize update + * can get lost as it may have been postponed to submission of writeback but + * that will never happen after we truncate page cache. + */ +int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset, + loff_t len) +{ + handle_t *handle; + loff_t size = i_size_read(inode); + + WARN_ON(!mutex_is_locked(&inode->i_mutex)); + if (offset > size || offset + len < size) + return 0; + + if (EXT4_I(inode)->i_disksize >= size) + return 0; + + handle = ext4_journal_start(inode, EXT4_HT_MISC, 1); + if (IS_ERR(handle)) + return PTR_ERR(handle); + ext4_update_i_disksize(inode, size); + ext4_mark_inode_dirty(handle, inode); + ext4_journal_stop(handle); + + return 0; +} + +/* * ext4_punch_hole: punches a hole in a file by releaseing the blocks * associated with the given offset and length * @@ -3729,9 +3758,13 @@ int ext4_punch_hole(struct inode *inode, last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
/* Now release the pages and zero block aligned part of pages*/ - if (last_block_offset > first_block_offset) + if (last_block_offset > first_block_offset) { + ret = ext4_update_disksize_before_punch(inode, offset, length); + if (ret) + goto out_dio; truncate_pagecache_range(inode, first_block_offset, last_block_offset); + }
if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) credits = ext4_writepage_trans_blocks(inode);