linux-toradex.git/fs/f2fs/namei.c, branch v3.10.94

f2fs: avoid deadlock during evict after f2fs_gc

2013-05-08T10:54:08+00:00

o Deadlock case #1

Thread 1:
- writeback_sb_inodes
 - do_writepages
  - f2fs_write_data_pages
   - write_cache_pages
    - f2fs_write_data_page
     - f2fs_balance_fs
      - wait mutex_lock(gc_mutex)

Thread 2:
- f2fs_balance_fs
 - mutex_lock(gc_mutex)
 - f2fs_gc
  - f2fs_iget
   - wait iget_locked(inode->i_lock)

Thread 3:
- do_unlinkat
 - iput
  - lock(inode->i_lock)
   - evict
    - inode_wait_for_writeback

o Deadlock case #2

Thread 1:
- __writeback_single_inode
 : set I_SYNC
  - do_writepages
   - f2fs_write_data_page
    - f2fs_balance_fs
     - f2fs_gc
      - iput
       - evict
        - inode_wait_for_writeback(I_SYNC)

In order to avoid this, even though iput is called with the zero-reference
count, we need to stop the eviction procedure if the inode is on writeback.
So this patch links f2fs_drop_inode which checks the I_SYNC flag.

Signed-off-by: Jaegeuk Kim

f2fs: add a tracepoint on f2fs_new_inode

2013-04-29T01:52:01+00:00

This can help when debugging the free nid allocation flows.

Reviewed-by: Namjae Jeon 
Signed-off-by: Jaegeuk Kim

f2fs: add tracepoints for sync & inode operations

2013-04-23T06:30:27+00:00

Add tracepoints in f2fs for tracing the syncing
operations like filesystem sync, file sync enter/exit.
It will helf to trace the code under debugging scenarios.

Also add tracepoints for tracing the various inode operations
like building inode, eviction of inode, link/unlike of
inodes.

Signed-off-by: Namjae Jeon 
Signed-off-by: Pankaj Kumar 
Acked-by: Steven Rostedt 
[Jaegeuk: combine and modify the tracepoint structures]
Signed-off-by: Jaegeuk Kim

f2fs: make is_multimedia_file code align with its name

2013-04-22T23:56:21+00:00

The code conditions put inside the function is_multimedia_file are
reverse to the name i.e, we need to negate the return to actually
check if the file is a multimedia file. So, change the code and usage
path to align both the name and comparision conditions.

Signed-off-by: Namjae Jeon 
Signed-off-by: Amit Sahrawat 
Signed-off-by: Jaegeuk Kim

f2fs: introduce a new global lock scheme

2013-04-09T09:21:18+00:00

In the previous version, f2fs uses global locks according to the usage types,
such as directory operations, block allocation, block write, and so on.

Reference the following lock types in f2fs.h.
enum lock_type {
	RENAME,		/* for renaming operations */
	DENTRY_OPS,	/* for directory operations */
	DATA_WRITE,	/* for data write */
	DATA_NEW,	/* for data allocation */
	DATA_TRUNC,	/* for data truncate */
	NODE_NEW,	/* for node allocation */
	NODE_TRUNC,	/* for node truncate */
	NODE_WRITE,	/* for node write */
	NR_LOCK_TYPE,
};

In that case, we lose the performance under the multi-threading environment,
since every types of operations must be conducted one at a time.

In order to address the problem, let's share the locks globally with a mutex
array regardless of any types.
So, let users grab a mutex and perform their jobs in parallel as much as
possbile.

For this, I propose a new global lock scheme as follows.

0. Data structure
 - f2fs_sb_info -> mutex_lock[NR_GLOBAL_LOCKS]
 - f2fs_sb_info -> node_write

1. mutex_lock_op(sbi)
 - try to get an avaiable lock from the array.
 - returns the index of the gottern lock variable.

2. mutex_unlock_op(sbi, index of the lock)
 - unlock the given index of the lock.

3. mutex_lock_all(sbi)
 - grab all the locks in the array before the checkpoint.

4. mutex_unlock_all(sbi)
 - release all the locks in the array after checkpoint.

5. block_operations()
 - call mutex_lock_all()
 - sync_dirty_dir_inodes()
 - grab node_write
 - sync_node_pages()

Note that,
 the pairs of mutex_lock_op()/mutex_unlock_op() and
 mutex_lock_all()/mutex_unlock_all() should be used together.

Signed-off-by: Jaegeuk Kim

f2fs: fix to give correct parent inode number for roll forward

2013-03-27T00:16:25+00:00

When we recover fsync'ed data after power-off-recovery, we should guarantee
that any parent inode number should be correct for each direct inode blocks.

So, let's make the following rules.

- The fsync should do checkpoint to all the inodes that were experienced hard
links.

- So, the only normal files can be recovered by roll-forward.

Signed-off-by: Jaegeuk Kim

f2fs: align f2fs maximum name length to linux based filesystem

2013-03-18T12:00:35+00:00

The maximum filename length supported in linux is 255 characters.
So let's follow that.

Signed-off-by: Namjae Jeon 
Signed-off-by: Amit Sahrawat 
Signed-off-by: Jaegeuk Kim

f2fs: unify string length declarations and usage

2012-12-28T02:27:53+00:00

This patch is intended to unify string length declarations and usage.
There are number of calls to strlen which return size_t object.
The size of this object depends on compiler if it will be bigger,
equal or even smaller than an unsigned int

Signed-off-by: Leon Romanovsky 
Signed-off-by: Jaegeuk Kim

f2fs: do f2fs_balance_fs in front of dir operations

2012-12-26T01:39:52+00:00

In order to conserve free sections to deal with the worst-case scenarios, f2fs
should be able to freeze all the directory operations especially when there are
not enough free sections. The f2fs_balance_fs() is for this use.

When FS utilization becomes almost 100%, directory operations can be failed due
to -ENOSPC frequently, which produces some dirty node pages occasionally.

Previously, in such a case, f2fs_balance_fs() is not able to be triggered since
it is triggered only if the directory operation ends up with success.

So, this patch triggers f2fs_balance_fs() at first before handling directory
operations.

Signed-off-by: Jaegeuk Kim

f2fs: make use of GFP_F2FS_ZERO for setting gfp_mask

2012-12-11T04:43:44+00:00

Since, GFP_NOFS and __GFP_ZERO is being used to set gfp_mask.
We can instead make use of already predefined macro GFP_F2FS_ZERO.

Signed-off-by: Namjae Jeon 
Signed-off-by: Amit Sahrawat