linux.git/fs/ext4/ialloc.c, branch v2.6.29

ext4: Print the find_group_flex() warning only once

2009-03-12T16:20:01+00:00

This is a short-term warning, and even printk_ratelimit() can result
in too much noise in system logs.  So only print it once as a warning.

Signed-off-by: "Theodore Ts'o"

ext4: fix ext4_free_inode() vs. ext4_claim_inode() race

2009-03-04T23:38:18+00:00

I was seeing fsck errors on inode bitmaps after a 4 thread
dbench run on a 4 cpu machine:

Inode bitmap differences: -50736 -(50752--50753) etc...

I believe that this is because ext4_free_inode() uses atomic
bitops, and although ext4_new_inode() *used* to also use atomic 
bitops for synchronization, commit 
393418676a7602e1d7d3f6e560159c65c8cbd50e changed this to use
the sb_bgl_lock, so that we could also synchronize against
read_inode_bitmap and initialization of uninit inode tables.

However, that change left ext4_free_inode using atomic bitops,
which I think leaves no synchronization between setting & 
unsetting bits in the inode table.

The below patch fixes it for me, although I wonder if we're 
getting at all heavy-handed with this spinlock...

Signed-off-by: Eric Sandeen 
Reviewed-by: Aneesh Kumar K.V 
Signed-off-by: "Theodore Ts'o"

ext4: Add fallback for find_group_flex

2009-02-21T17:13:24+00:00

This is a workaround for find_group_flex() which badly needs to be
replaced.  One of its problems (besides ignoring the Orlov algorithm)
is that it is a bit hyperactive about returning failure under
suspicious circumstances.  This can lead to spurious ENOSPC failures
even when there are inodes still available.

Work around this for now by retrying the search using
find_group_other() if find_group_flex() returns -1.  If
find_group_other() succeeds when find_group_flex() has failed, log a
warning message.

A better block/inode allocator that will fix this problem for real has
been queued up for the next merge window.

Signed-off-by: "Theodore Ts'o"

ext4: Remove "extents" mount option

2009-01-06T19:53:16+00:00

This mount option is largely superfluous, and in fact the way it was
implemented was buggy; if a filesystem which did not have the extents
feature flag was mounted -o extents, the filesystem would attempt to
create and use extents-based file even though the extents feature flag
was not eabled.  The simplest thing to do is to nuke the mount option
entirely.  It's not all that useful to force the non-creation of new
extent-based files if the filesystem can support it.

Signed-off-by: "Theodore Ts'o"

ext4: Add markers for better debuggability

2009-01-04T01:03:21+00:00

Signed-off-by: "Theodore Ts'o"

ext4: mark the blocks/inode bitmap beyond end of group as used

2009-01-06T02:46:04+00:00

We need to mark the block/inode bitmap beyond the end of the group
with '1'.

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: "Theodore Ts'o" 
Cc: stable@kernel.org

ext4: Use new buffer_head flag to check uninit group bitmaps initialization

2009-01-06T02:49:55+00:00

For uninit block group, the on-disk bitmap is not initialized. That
implies we cannot depend on the uptodate flag on the bitmap
buffer_head to find bitmap validity.  Use a new buffer_head flag which
would be set after we properly initialize the bitmap.  This also
prevents (re-)initializing the uninit group bitmap every time we call 
ext4_read_block_bitmap().

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: "Theodore Ts'o" 
Cc: stable@kernel.org

ext4: Fix the race between read_inode_bitmap() and ext4_new_inode()

2009-01-06T02:38:14+00:00

We need to make sure we update the inode bitmap and clear
EXT4_BG_INODE_UNINIT flag with sb_bgl_lock held, since
ext4_read_inode_bitmap() looks at EXT4_BG_INODE_UNINIT to decide
whether to initialize the inode bitmap each time it is called.
(introduced by commit c806e68f.)

ext4_read_inode_bitmap does:

spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));
if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
	ext4_init_inode_bitmap(sb, bh, block_group, desc);

and ext4_new_inode does
if (!ext4_set_bit_atomic(sb_bgl_lock(sbi, group),
                   ino, inode_bitmap_bh->b_data))
		   ......
		   ...
spin_lock(sb_bgl_lock(sbi, group));

gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
i.e., on allocation we update the bitmap then we take the sb_bgl_lock
and clear the EXT4_BG_INODE_UNINIT flag. What can happen is a
parallel ext4_read_inode_bitmap can zero out the bitmap in between
the above ext4_set_bit_atomic and spin_lock(sb_bg_lock..)

The race results in below user visible errors
EXT4-fs error (device sdb1): ext4_free_inode: bit already cleared for inode 168449
EXT4-fs warning (device sdb1): ext4_unlink: Deleting nonexistent file ...
EXT4-fs warning (device sdb1): ext4_rmdir: empty directory has too many links ...
# ls -al /mnt/tmp/f/p369/d3/d6/d39/db2/dee/d10f/d3f/l71
ls: /mnt/tmp/f/p369/d3/d6/d39/db2/dee/d10f/d3f/l71: Stale NFS file handle

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: "Theodore Ts'o" 
Cc: stable@kernel.org

ext4: code cleanup

2009-01-04T03:33:39+00:00

Rename some variables.  We also unlock locks in the reverse order we
acquired as a part of cleanup.

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: "Theodore Ts'o"

ext4: Use high 16 bits of the block group descriptor's free counts fields

2009-01-06T03:20:24+00:00

Rename the lower bits with suffix _lo and add helper
to access the values. Also rename bg_itable_unused_hi
to bg_pad as in e2fsprogs.

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: "Theodore Ts'o"