diff options
| author | Allison Henderson <achender@linux.vnet.ibm.com> | 2011-09-06 21:53:01 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2011-09-06 21:53:01 -0400 |
| commit | 02fac1297eb3f471a27368271aadd285548297b0 (patch) | |
| tree | d0008f0aa889dba759cb780e8e805b30953083cf /fs/ext4/inode.c | |
| parent | 189e868fa8fdca702eb9db9d8afc46b5cb9144c9 (diff) | |
ext4: fix partial page writes
While running extended fsx tests to verify the preceeding patches,
a similar bug was also found in the write operation
When ever a write operation begins or ends in a hole,
or extends EOF, the partial page contained in the hole
or beyond EOF needs to be zeroed out.
To correct this the new ext4_discard_partial_page_buffers_no_lock
routine is used to zero out the partial page, but only for buffer
heads that are already unmapped.
Signed-off-by: Allison Henderson <achender@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/inode.c')
| -rw-r--r-- | fs/ext4/inode.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index f86b149fb8b..6ecc93979e4 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2255,6 +2255,7 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping, pgoff_t index; struct inode *inode = mapping->host; handle_t *handle; + loff_t page_len; index = pos >> PAGE_CACHE_SHIFT; @@ -2301,6 +2302,13 @@ retry: */ if (pos + len > inode->i_size) ext4_truncate_failed_write(inode); + } else { + page_len = pos & (PAGE_CACHE_SIZE - 1); + if (page_len > 0) { + ret = ext4_discard_partial_page_buffers_no_lock(handle, + inode, page, pos - page_len, page_len, + EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED); + } } if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) @@ -2343,6 +2351,7 @@ static int ext4_da_write_end(struct file *file, loff_t new_i_size; unsigned long start, end; int write_mode = (int)(unsigned long)fsdata; + loff_t page_len; if (write_mode == FALL_BACK_TO_NONDELALLOC) { if (ext4_should_order_data(inode)) { @@ -2391,6 +2400,16 @@ static int ext4_da_write_end(struct file *file, } ret2 = generic_write_end(file, mapping, pos, len, copied, page, fsdata); + + page_len = PAGE_CACHE_SIZE - + ((pos + copied - 1) & (PAGE_CACHE_SIZE - 1)); + + if (page_len > 0) { + ret = ext4_discard_partial_page_buffers_no_lock(handle, + inode, page, pos + copied - 1, page_len, + EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED); + } + copied = ret2; if (ret2 < 0) ret = ret2; |