diff options
author | Dmitry Monakhov <dmonakhov@openvz.org> | 2010-03-02 13:08:51 (GMT) |
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committer | Theodore Ts'o <tytso@mit.edu> | 2010-03-02 13:08:51 (GMT) |
commit | 67eeb5685d2a211c0252ac7884142e503c759500 (patch) | |
tree | 48f01e99b3cd52e20d5ac253ddd87e45a0a61af0 /fs/ext4 | |
parent | 273df556b6ee2065bfe96edab5888d3dc9b108d8 (diff) | |
download | linux-67eeb5685d2a211c0252ac7884142e503c759500.tar.xz |
ext4: Fix ext4_quota_write cross block boundary behaviour
We always assume what dquot update result in changes in one data block
But ext4_quota_write() function may handle cross block boundary writes
In fact if this ever happen it will result in incorrect journal
credits reservation, and later a BUG_ON. As soon this never happen
the boundary cross loop is NOOP. In order to make things straight
let's remove this loop and assert cross boundary condition.
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
-rw-r--r-- | fs/ext4/super.c | 69 |
1 files changed, 34 insertions, 35 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 5a18e9e..ad1ee5f 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -4010,9 +4010,7 @@ static ssize_t ext4_quota_write(struct super_block *sb, int type, ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb); int err = 0; int offset = off & (sb->s_blocksize - 1); - int tocopy; int journal_quota = EXT4_SB(sb)->s_qf_names[type] != NULL; - size_t towrite = len; struct buffer_head *bh; handle_t *handle = journal_current_handle(); @@ -4022,52 +4020,53 @@ static ssize_t ext4_quota_write(struct super_block *sb, int type, (unsigned long long)off, (unsigned long long)len); return -EIO; } + /* + * Since we account only one data block in transaction credits, + * then it is impossible to cross a block boundary. + */ + if (sb->s_blocksize - offset < len) { + ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)" + " cancelled because not block aligned", + (unsigned long long)off, (unsigned long long)len); + return -EIO; + } + mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA); - while (towrite > 0) { - tocopy = sb->s_blocksize - offset < towrite ? - sb->s_blocksize - offset : towrite; - bh = ext4_bread(handle, inode, blk, 1, &err); - if (!bh) + bh = ext4_bread(handle, inode, blk, 1, &err); + if (!bh) + goto out; + if (journal_quota) { + err = ext4_journal_get_write_access(handle, bh); + if (err) { + brelse(bh); goto out; - if (journal_quota) { - err = ext4_journal_get_write_access(handle, bh); - if (err) { - brelse(bh); - goto out; - } } - lock_buffer(bh); - memcpy(bh->b_data+offset, data, tocopy); - flush_dcache_page(bh->b_page); - unlock_buffer(bh); - if (journal_quota) - err = ext4_handle_dirty_metadata(handle, NULL, bh); - else { - /* Always do at least ordered writes for quotas */ - err = ext4_jbd2_file_inode(handle, inode); - mark_buffer_dirty(bh); - } - brelse(bh); - if (err) - goto out; - offset = 0; - towrite -= tocopy; - data += tocopy; - blk++; } + lock_buffer(bh); + memcpy(bh->b_data+offset, data, len); + flush_dcache_page(bh->b_page); + unlock_buffer(bh); + if (journal_quota) + err = ext4_handle_dirty_metadata(handle, NULL, bh); + else { + /* Always do at least ordered writes for quotas */ + err = ext4_jbd2_file_inode(handle, inode); + mark_buffer_dirty(bh); + } + brelse(bh); out: - if (len == towrite) { + if (err) { mutex_unlock(&inode->i_mutex); return err; } - if (inode->i_size < off+len-towrite) { - i_size_write(inode, off+len-towrite); + if (inode->i_size < off + len) { + i_size_write(inode, off + len); EXT4_I(inode)->i_disksize = inode->i_size; } inode->i_mtime = inode->i_ctime = CURRENT_TIME; ext4_mark_inode_dirty(handle, inode); mutex_unlock(&inode->i_mutex); - return len - towrite; + return len; } #endif |