ext4: Invert lock ordering of page_lock and transaction start in delalloc
With the reverse locking, we need to start a transation before taking
the page lock, so in ext4_da_writepages() we need to break the write-out
into chunks, and restart the journal for each chunck to ensure the
write-out fits in a single transaction.
Updated patch from Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
which fixes delalloc sync hang with journal lock inversion, and address
the performance regression issue.
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index dabc3b6..42c4c0c 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2565,6 +2565,7 @@
int err = 0, depth, ret;
unsigned long allocated = 0;
struct ext4_allocation_request ar;
+ loff_t disksize;
__clear_bit(BH_New, &bh_result->b_state);
ext_debug("blocks %u/%lu requested for inode %u\n",
@@ -2755,8 +2756,13 @@
newblock = ext_pblock(&newex);
allocated = ext4_ext_get_actual_len(&newex);
outnew:
- if (extend_disksize && inode->i_size > EXT4_I(inode)->i_disksize)
- EXT4_I(inode)->i_disksize = inode->i_size;
+ if (extend_disksize) {
+ disksize = ((loff_t) iblock + ar.len) << inode->i_blkbits;
+ if (disksize > i_size_read(inode))
+ disksize = i_size_read(inode);
+ if (disksize > EXT4_I(inode)->i_disksize)
+ EXT4_I(inode)->i_disksize = disksize;
+ }
set_buffer_new(bh_result);