user/sven/linux.git/fs/f2fs, branch v3.8

f2fs: use _safe() version of list_for_each

2013-01-22T01:49:00Z

This is calling list_del() inside a loop which is a problem when we try move to the next item on the list. I've converted it to use the _safe version. And also, as a cleanup, I've converted it to use list_for_each_entry instead of list_for_each. Signed-off-by: Dan Carpenter Reviewed-by: Dmitry Torokhov Signed-off-by: Jaegeuk Kim

f2fs: add comments of start_bidx_of_node

2013-01-22T01:48:59Z

The caller of start_bidx_of_node() should give proper node offsets which point only direct node blocks. Otherwise, it is a caller's bug. This patch adds comments to make it clear. Reported-by: Dan Carpenter Signed-off-by: Jaegeuk Kim

f2fs: avoid issuing small bios due to several dirty node pages

2013-01-22T01:48:59Z

If some small bios of dirty node pages are supposed to be issued during the sequential data writes, there-in well-produced consecutive data bios are able to be split by the small node bios, resulting in performance degradation. So, let's collect a number of dirty node pages until reaching a threshold. And, by default, I set the threshold as 2MB, a segment size. This improves sequential write performance on i5, 512GB SSD (830 w/ SATA2) as follows. Before: 231 MB/s -> After: 255 MB/s Signed-off-by: Jaegeuk Kim Reviewed-by: Namjae Jeon

f2fs: support swapfile

2013-01-22T01:48:58Z

This patch adds f2fs_bmap operation to the data address space. This enables f2fs to support swapfile. Signed-off-by: Jaegeuk Kim

f2fs: add remap_pages as generic_file_remap_pages

2013-01-22T01:48:58Z

This was added for all the file systems before. See the following commit. commit id: 0b173bc4daa8f8ec03a85abf5e47b23502ff80af [PATCH] mm: kill vma flag VM_CAN_NONLINEAR This patch moves actual ptes filling for non-linear file mappings into special vma operation: ->remap_pages(). File system must implement this method to get non-linear mappings support, if it uses filemap_fault() then generic_file_remap_pages() can be used. Now device drivers can implement this method and obtain nonlinear vma support." Signed-off-by: Jaegeuk Kim

f2fs: add __init to functions in init_f2fs_fs

2013-01-22T01:48:38Z

Add __init to functions in init_f2fs_fs for code consistency. Signed-off-by: Namjae Jeon Signed-off-by: Amit Sahrawat Signed-off-by: Jaegeuk Kim

f2fs: fix the debugfs entry creation path

2013-01-15T11:19:15Z

As the "status" debugfs entry will be maintained for entire F2FS filesystem irrespective of the number of partitions. So, we can move the initialization to the init part of the f2fs and destroy will be done from exit part. After making changes, for individual partition mount - entry creation code will not be executed. Signed-off-by: Jianpeng Ma Signed-off-by: Namjae Jeon Signed-off-by: Amit Sahrawat Signed-off-by: Jaegeuk Kim

f2fs: add global mutex_lock to protect f2fs_stat_list

2013-01-15T11:18:29Z

There is an race condition between umounting f2fs and reading f2fs/status, which results in oops. Fox example: Thread A Thread B umount f2fs cat f2fs/status f2fs_destroy_stats() { stat_show() { list_for_each_entry_safe(&f2fs_stat_list) list_del(&si->stat_list); mutex_lock(&si->stat_lock); si->sbi = NULL; mutex_unlock(&si->stat_lock); kfree(sbi->stat_info); } mutex_lock(&si->stat_lock) <- si is gone. ... } Solution with a global lock: f2fs_stat_mutex: Thread A Thread B umount f2fs cat f2fs/status f2fs_destroy_stats() { stat_show() { mutex_lock(&f2fs_stat_mutex); list_del(&si->stat_list); mutex_unlock(&f2fs_stat_mutex); kfree(sbi->stat_info); mutex_lock(&f2fs_stat_mutex); } list_for_each_entry_safe(&f2fs_stat_list) ... mutex_unlock(&f2fs_stat_mutex); } Signed-off-by: Jianpeng Ma [jaegeuk.kim@samsung.com: fix typos, description, and remove the existing lock] Signed-off-by: Jaegeuk Kim

f2fs: remove the blk_plug usage in f2fs_write_data_pages

2013-01-15T11:18:16Z

Let's consider the usage of blk_plug in f2fs_write_data_pages(). We can come up with the two issues: lock contention and task awareness. 1. Merging bios prior to grabing "queue lock" The f2fs merges consecutive IOs in the file system level before submitting any bios, which is similar with the back merge by the plugging mechanism in attempt_plug_merge(). Both of them need to acquire no queue lock. 2. Merging policy with respect to tasks The f2fs merges IOs as much as possible regardless of tasks, while blk-plugging is conducted on a basis of tasks. As we can understand there are trade-offs, f2fs tries to maximize the write performance with well-merged bios. As a result, if f2fs produces many consecutive but separated bios in writepages(), it would be good to use blk-plugging since f2fs would be able to avoid queue lock contention in the block layer by merging them. But, f2fs merges IOs and submit one bio, which means that there are not much chances to merge bios by attempt_plug_merge(). However, f2fs has already been used blk_plug by triggering generic_writepages() in f2fs_write_data_pages(). So to make the overall code consistency, I'd like to remove blk_plug there. Signed-off-by: Namjae Jeon Signed-off-by: Amit Sahrawat Signed-off-by: Jaegeuk Kim

f2fs: avoid redundant time update for parent directory in f2fs_delete_entry

2013-01-14T00:43:27Z

In call to f2fs_delete_entry, 'dir' time modification code is put at two places. So, remove the redundant code for timing update. Signed-off-by: Namjae Jeon Signed-off-by: Amit Sahrawat Signed-off-by: Jaegeuk Kim