switch a bunch of places to mnt_want_write_file()

it's both faster (in case when file has been opened for write) and cleaner.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Conflicts:
	fs/ext4/ioctl.c
	fs/nfsd/nfs4recover.c
	fs/xfs/xfs_ioctl.c

Change-Id: Ibb2cc434d8d320d7c1790add3108330f6d5b2fc5
vfs: mnt_drop_write_file()

new helper (wrapper around mnt_drop_write()) to be used in pair with
mnt_want_write_file().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Conflicts:
	fs/ext4/ioctl.c
	fs/xfs/xfs_ioctl.c

Change-Id: Idcde3c3eba747966dcfc692f1a2f473cbfdf050a
f2fs: fix wrong condition check

While an orphan inode has zero link_count, f2fs_gc is able to select the inode
for foreground gc.

- f2fs_gc
 - do_garbage_collect
   - gc_data_segment
     : f2fs_iget is failed
     : get_valid_blocks() != 0, so that retry
--> here we got the infinite loop.

This patch resolved this issue.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
f2fs: reuse the locked dnode page and its inode

This patch fixes the following deadlock bug during the recovery.

INFO: task mount:1322 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
mount           D ffffffff81125870     0  1322   1266 0x00000000
 ffff8801207e39d8 0000000000000046 ffff88012ab1dee0 0000000000000046
 ffff8801207e3a08 ffff880115903f40 ffff8801207e3fd8 ffff8801207e3fd8
 ffff8801207e3fd8 ffff880115903f40 ffff8801207e39d8 ffff88012fc94520
Call Trace:
[<ffffffff81125870>] ? __lock_page+0x70/0x70
[<ffffffff816a92d9>] schedule+0x29/0x70
[<ffffffff816a93af>] io_schedule+0x8f/0xd0
[<ffffffff8112587e>] sleep_on_page+0xe/0x20
[<ffffffff816a649a>] __wait_on_bit_lock+0x5a/0xc0
[<ffffffff81125867>] __lock_page+0x67/0x70
[<ffffffff8106c7b0>] ? autoremove_wake_function+0x40/0x40
[<ffffffff81126857>] find_lock_page+0x67/0x80
[<ffffffff8112698f>] find_or_create_page+0x3f/0xb0
[<ffffffffa03901a8>] ? sync_inode_page+0xa8/0xd0 [f2fs]
[<ffffffffa038fdf7>] get_node_page+0x67/0x180 [f2fs]
[<ffffffffa039818b>] recover_fsync_data+0xacb/0xff0 [f2fs]
[<ffffffff816aaa1e>] ? _raw_spin_unlock+0x3e/0x40
[<ffffffffa0389634>] f2fs_fill_super+0x7d4/0x850 [f2fs]
[<ffffffff81184cf9>] mount_bdev+0x1c9/0x210
[<ffffffffa0388e60>] ? validate_superblock+0x180/0x180 [f2fs]
[<ffffffffa0387635>] f2fs_mount+0x15/0x20 [f2fs]
[<ffffffff81185a13>] mount_fs+0x43/0x1b0
[<ffffffff81145ba0>] ? __alloc_percpu+0x10/0x20
[<ffffffff811a0796>] vfs_kern_mount+0x76/0x120
[<ffffffff811a2cb7>] do_mount+0x237/0xa10
[<ffffffff81140b9b>] ? strndup_user+0x5b/0x80
[<ffffffff811a3520>] SyS_mount+0x90/0xe0
[<ffffffff816b3502>] system_call_fastpath+0x16/0x1b

The bug is triggered when check_index_in_prev_nodes tries to get the direct
node page by calling get_node_page.
At this point, if the direct node page is already locked by get_dnode_of_data,
its caller, we got a deadlock condition.

This patch adds additional condition check for the reuse of locked direct node
pages prior to the get_node_page call.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
f2fs: fix to handle do_recover_data errors

This patch adds error handling codes of check_index_in_prev_nodes and its
caller, do_recover_data.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
f2fs: should not make_bad_inode on f2fs_link failure

If -ENOSPC is met during f2fs_link, we should not make the inode as bad.
The inode is still alive.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
f2fs: use ihold

Use the following helper function committed by Al.

commit 7de9c6ee3ecffd99e1628e81a5ea5468f7581a1f
Author: Al Viro <viro@zeniv.linux.org.uk>
Date:   Sat Oct 23 11:11:40 2010 -0400

    new helper: ihold()

...

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
f2fs: dereferencing an ERR_PTR

There is an error path where "dir" is an ERR_PTR.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
f2fs: align data types between on-disk and in-memory block addresses

The on-disk block address is defined as __le32, but in-memory block address,
block_t, does as u64.

Let's synchronize them to 32 bits.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
f2fs: push some variables to debug part

Some, counters are needed only for the statistical information
while debugging.
So, those can be controlled using CONFIG_F2FS_STAT_FS,
pushing the usage for few variables under this flag.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
f2fs: remove unneeded initializations in f2fs_parent_dir

There is no need to initialize few pointers in f2fs_parent_dir
as the values are not checked and instead directly initialized
values are used.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
f2fs: optimize several routines in node.h

There are various functions with common code which could be separated
out to make common routines. So, made new routines and in order to
retain the same call path and no major changes, written some macros
to access those routines.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
f2fs: return proper error from start_gc_thread

when there is an error from kthread_run, then return proper error
rather than returning -ENOMEM.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
f2fs: iput only if whole data blocks are flushed

If there remains some unwritten blocks from the recovery, we should not call
iput on that directory inode.
Otherwise, we can loose some dentry blocks after the recovery.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
f2fs: fix dentry recovery routine

The error scenario is:
1. create /a
(1.a link /a /b)
2. sync
3. unlinke /a
4. create /a
5. fsync /a
6. Sudden power-off

When the f2fs recovers the fsynced dentry, /a, we discover an exsiting dentry at
f2fs_find_entry() in recover_dentry().

In such the case, we should unlink the existing dentry and its inode
and then recover newly created dentry.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
f2fs: fix incorrect iputs during the dentry recovery

- iget/iput flow in the dentry recovery process

1. *dir* = f2fs_iget
2. set FI_DELAY_IPUT to *dir*
3. add *dir* to the dirty_dir_list
		   - __f2fs_add_link
		     - recover_dentry)
4. iput *dir* by remove_dirty_dir_inode
		   - sync_dirty_dir_inodes
		     - write_chekcpoint

If *dir*'s i_count is not 1 (i.e., root dir), remove_dirty_dir_inode is called
later and then iput is triggered again due to the FI_DELAY_IPUT flag.
So, let's unset the flag properly once iput is triggered.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
f2fs: cover cp_file information with ilock

If a file is linked with other files, it should be checkpointed at every fsync
calls.
For this, we use set_cp_file() with FADVISE_CP_BIT, but previously we didn't
cover the flag by the global lock.
This patch fixes that the inode page stores this correctly.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
f2fs: handle errors from get_node_page calls

Add check for error pointers returned from get_node_page in order to
avoid dereferencing a bad address on the next use.

Signed-off-by: Jason Hrycay <jason.hrycay@motorola.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
f2fs: reorganise the function get_victim_by_default

Fix the function get_victim_by_default, where it checks
for the condition  that p.min_segno != NULL_SEGNO as
shown:

if (p.min_segno != NULL_SEGNO)
           goto got_it;

and if above condition is true then

got_it:
        if (p.min_segno != NULL_SEGNO) {

So this condition is being checked twice. Hence move the goto
statement after the if condition so that duplication of condition
check is avoided.

Also this function makes a call to get_max_cost() to compute
the max cost based on the f2fs_sbi_info and victim policy. Since
get_max_cost depends on on three parameters of victim_sel_policy
=> alloc_mode, gc_mode & ofs_unit, once this victim policy is
initialised, these value will not change till the execution
time of get_victim_by_default() & also f2fs_sbi_info structure
parameters will not change.

Hence making calls to get_max_cost() in while loop does not seems to
be a good point. Instead we can call it once in begining and store
the results in local variable, which later can serve our purpose
for comparing the cost with max cost inside the while loop.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Pankaj Kumar <pankaj.km@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
f2fs: fix iget/iput of dir during recovery

It is possible that iput is skipped after iget during the recovery.

In recover_dentry(),
 dir = f2fs_iget();
 ...
 if (de && inode->i_ino == le32_to_cpu(de->ino))
	goto out;

In this case, this dir is not able to be added in dirty_dir_inode_list.
The actual linking is done only when set_page_dirty() is called.

So let's add this newly got inode into the list explicitly, and put it at the
end of the recovery routine.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>