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authorDmitry Monakhov <dmonakhov@openvz.org>2010-03-02 08:08:51 -0500
committerTheodore Ts'o <tytso@mit.edu>2010-03-02 08:08:51 -0500
commit67eeb5685d2a211c0252ac7884142e503c759500 (patch)
tree48f01e99b3cd52e20d5ac253ddd87e45a0a61af0 /fs
parent273df556b6ee2065bfe96edab5888d3dc9b108d8 (diff)
downloadop-kernel-dev-67eeb5685d2a211c0252ac7884142e503c759500.zip
op-kernel-dev-67eeb5685d2a211c0252ac7884142e503c759500.tar.gz
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')
-rw-r--r--fs/ext4/super.c69
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
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