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| author | Namjae Jeon <namjae.jeon@samsung.com> | 2014-12-12 16:57:26 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-12-13 12:42:51 -0800 |
| commit | c0ef0cc9d277f0f2a83b5a287a816b3916d9f026 (patch) | |
| tree | 8dc88d4fc0de0bb485578ad6482044a0ecfdef2d | |
| parent | f441ada0040ed35572df517293b44a9998cc022d (diff) | |
| download | lwn-c0ef0cc9d277f0f2a83b5a287a816b3916d9f026.tar.gz lwn-c0ef0cc9d277f0f2a83b5a287a816b3916d9f026.zip | |
fat: fix data past EOF resulting from fsx testsuite
When running FSX with direct I/O mode, fsx resulted in DATA past EOF issues.
fsx ./file2 -Z -r 4096 -w 4096
...
..
truncating to largest ever: 0x907c
fallocating to largest ever: 0x11137
truncating to largest ever: 0x2c6fe
truncating to largest ever: 0x2cfdf
fallocating to largest ever: 0x40000
Mapped Read: non-zero data past EOF (0x18628) page offset 0x629 is 0x2a4e
...
..
The reason being, it is doing a truncate down, but the zeroing does not
happen on the last block boundary when offset is not aligned. Even though
it calls truncate_setsize()->truncate_inode_pages()->
truncate_inode_pages_range() and considers the partial zeroout but it
retrieves the page using find_lock_page() - which only looks the page in
the cache. So, zeroing out does not happen in case of direct IO.
Make a truncate page based around block_truncate_page for FAT filesystem
and invoke that helper to zerout in case the offset is not aligned with
the blocksize.
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/fat/fat.h | 1 | ||||
| -rw-r--r-- | fs/fat/file.c | 3 | ||||
| -rw-r--r-- | fs/fat/inode.c | 12 |
3 files changed, 16 insertions, 0 deletions
diff --git a/fs/fat/fat.h b/fs/fat/fat.h index e0c4ba39a377..64e295e8ff38 100644 --- a/fs/fat/fat.h +++ b/fs/fat/fat.h @@ -370,6 +370,7 @@ extern int fat_file_fsync(struct file *file, loff_t start, loff_t end, int datasync); /* fat/inode.c */ +extern int fat_block_truncate_page(struct inode *inode, loff_t from); extern void fat_attach(struct inode *inode, loff_t i_pos); extern void fat_detach(struct inode *inode); extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos); diff --git a/fs/fat/file.c b/fs/fat/file.c index 85f79a89e747..8429c68e3057 100644 --- a/fs/fat/file.c +++ b/fs/fat/file.c @@ -443,6 +443,9 @@ int fat_setattr(struct dentry *dentry, struct iattr *attr) } if (attr->ia_valid & ATTR_SIZE) { + error = fat_block_truncate_page(inode, attr->ia_size); + if (error) + goto out; down_write(&MSDOS_I(inode)->truncate_lock); truncate_setsize(inode, attr->ia_size); fat_truncate_blocks(inode, attr->ia_size); diff --git a/fs/fat/inode.c b/fs/fat/inode.c index 756aead10d96..7b41a2dcdd76 100644 --- a/fs/fat/inode.c +++ b/fs/fat/inode.c @@ -294,6 +294,18 @@ static sector_t _fat_bmap(struct address_space *mapping, sector_t block) return blocknr; } +/* + * fat_block_truncate_page() zeroes out a mapping from file offset `from' + * up to the end of the block which corresponds to `from'. + * This is required during truncate to physically zeroout the tail end + * of that block so it doesn't yield old data if the file is later grown. + * Also, avoid causing failure from fsx for cases of "data past EOF" + */ +int fat_block_truncate_page(struct inode *inode, loff_t from) +{ + return block_truncate_page(inode->i_mapping, from, fat_get_block); +} + static const struct address_space_operations fat_aops = { .readpage = fat_readpage, .readpages = fat_readpages, |