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| author | Jan Kara <jack@suse.cz> | 2009-12-08 21:24:33 -0500 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2009-12-08 21:24:33 -0500 |
| commit | b9a4207d5e911b938f73079a83cc2ae10524ec7f (patch) | |
| tree | 6926354a2c6cc8e5f0e930845774ffe73d3766b8 | |
| parent | 24b584240a0006ea7436cd35f5e8983eb76f1e6f (diff) | |
| download | blackbird-op-linux-b9a4207d5e911b938f73079a83cc2ae10524ec7f.tar.gz blackbird-op-linux-b9a4207d5e911b938f73079a83cc2ae10524ec7f.zip | |
ext4: Avoid data / filesystem corruption when write fails to copy data
When ext4_write_begin fails after allocating some blocks or
generic_perform_write fails to copy data to write, we truncate blocks
already instantiated beyond i_size. Although these blocks were never
inside i_size, we have to truncate the pagecache of these blocks so
that corresponding buffers get unmapped. Otherwise subsequent
__block_prepare_write (called because we are retrying the write) will
find the buffers mapped, not call ->get_block, and thus the page will
be backed by already freed blocks leading to filesystem and data
corruption.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
| -rw-r--r-- | fs/ext4/inode.c | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index d3f99e9e8a31..0e2ea572856c 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1492,6 +1492,16 @@ static int do_journal_get_write_access(handle_t *handle, return ext4_journal_get_write_access(handle, bh); } +/* + * Truncate blocks that were not used by write. We have to truncate the + * pagecache as well so that corresponding buffers get properly unmapped. + */ +static void ext4_truncate_failed_write(struct inode *inode) +{ + truncate_inode_pages(inode->i_mapping, inode->i_size); + ext4_truncate(inode); +} + static int ext4_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) @@ -1557,7 +1567,7 @@ retry: ext4_journal_stop(handle); if (pos + len > inode->i_size) { - ext4_truncate(inode); + ext4_truncate_failed_write(inode); /* * If truncate failed early the inode might * still be on the orphan list; we need to @@ -1667,7 +1677,7 @@ static int ext4_ordered_write_end(struct file *file, ret = ret2; if (pos + len > inode->i_size) { - ext4_truncate(inode); + ext4_truncate_failed_write(inode); /* * If truncate failed early the inode might still be * on the orphan list; we need to make sure the inode @@ -1709,7 +1719,7 @@ static int ext4_writeback_write_end(struct file *file, ret = ret2; if (pos + len > inode->i_size) { - ext4_truncate(inode); + ext4_truncate_failed_write(inode); /* * If truncate failed early the inode might still be * on the orphan list; we need to make sure the inode @@ -1772,7 +1782,7 @@ static int ext4_journalled_write_end(struct file *file, if (!ret) ret = ret2; if (pos + len > inode->i_size) { - ext4_truncate(inode); + ext4_truncate_failed_write(inode); /* * If truncate failed early the inode might still be * on the orphan list; we need to make sure the inode @@ -3048,7 +3058,7 @@ retry: * i_size_read because we hold i_mutex. */ if (pos + len > inode->i_size) - ext4_truncate(inode); + ext4_truncate_failed_write(inode); } if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) |
