kernel.git/fs/f2fs/checkpoint.c, branch linux-3.10.y

f2fs: check truncation of mapping after lock_page

2013-04-29T02:19:32Z

We call lock_page when we need to update a page after readpage. Between grab and lock page, the page can be truncated by other thread. So, we should check the page after lock_page whether it was truncated or not. Signed-off-by: Jaegeuk Kim

f2fs: give a chance to merge IOs by IO scheduler

2013-04-26T01:35:10Z

Previously, background GC submits many 4KB read requests to load victim blocks and/or its (i)node blocks. ... f2fs_gc : f2fs_readpage: ino = 1, page_index = 0xb61, blkaddr = 0x3b964ed f2fs_gc : block_rq_complete: 8,16 R () 499854968 + 8 [0] f2fs_gc : f2fs_readpage: ino = 1, page_index = 0xb6f, blkaddr = 0x3b964ee f2fs_gc : block_rq_complete: 8,16 R () 499854976 + 8 [0] f2fs_gc : f2fs_readpage: ino = 1, page_index = 0xb79, blkaddr = 0x3b964ef f2fs_gc : block_rq_complete: 8,16 R () 499854984 + 8 [0] ... However, by the fact that many IOs are sequential, we can give a chance to merge the IOs by IO scheduler. In order to do that, let's use blk_plug. ... f2fs_gc : f2fs_iget: ino = 143 f2fs_gc : f2fs_readpage: ino = 143, page_index = 0x1c6, blkaddr = 0x2e6ee f2fs_gc : f2fs_iget: ino = 143 f2fs_gc : f2fs_readpage: ino = 143, page_index = 0x1c7, blkaddr = 0x2e6ef : block_rq_complete: 8,16 R () 1519616 + 8 [0] : block_rq_complete: 8,16 R () 1519848 + 8 [0] : block_rq_complete: 8,16 R () 1520432 + 96 [0] : block_rq_complete: 8,16 R () 1520536 + 104 [0] : block_rq_complete: 8,16 R () 1521008 + 112 [0] : block_rq_complete: 8,16 R () 1521440 + 152 [0] : block_rq_complete: 8,16 R () 1521688 + 144 [0] : block_rq_complete: 8,16 R () 1522128 + 192 [0] : block_rq_complete: 8,16 R () 1523256 + 328 [0] ... Note that this issue should be addressed in checkpoint, and some readahead flows too. Reviewed-by: Namjae Jeon Signed-off-by: Jaegeuk Kim

f2fs: add tracepoints to debug checkpoint request

2013-04-23T10:16:37Z

Add tracepoints to debug checkpoint request. Signed-off-by: Namjae Jeon Signed-off-by: Pankaj Kumar Acked-by: Steven Rostedt [Jaegeuk: change expressions] Signed-off-by: Jaegeuk Kim

f2fs: introduce a new global lock scheme

2013-04-09T09:21:18Z

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: change GC bitmaps to apply the section granularity

2013-04-03T08:27:49Z

This patch removes a bitmap for victim segments selected by foreground GC, and modifies the other bitmap for victim segments selected by background GC. 1) foreground GC bitmap : We don't need to manage this, since we just only one previous victim section number instead of the whole victim history. The f2fs uses the victim section number in order not to allocate currently GC'ed section to current active logs. 2) background GC bitmap : This bitmap is used to avoid selecting victims repeatedly by background GCs. In addition, the victims are able to be selected by foreground GCs, since there is no need to read victim blocks during foreground GCs. By the fact that the foreground GC reclaims segments in a section unit, it'd be better to manage this bitmap based on the section granularity. Reviewed-by: Namjae Jeon Signed-off-by: Jaegeuk Kim

f2fs: reduce unncessary locking pages during read

2013-03-20T09:30:06Z

This patch reduces redundant locking and unlocking pages during read operations. In f2fs_readpage, let's use wait_on_page_locked() instead of lock_page. And then, when we need to modify any data finally, let's lock the page so that we can avoid lock contention. [readpage rule] - The f2fs_readpage returns unlocked page, or released page too in error cases. - Its caller should handle read error, -EIO, after locking the page, which indicates read completion. - Its caller should check PageUptodate after grab_cache_page. Signed-off-by: Changman Lee Reviewed-by: Namjae Jeon Signed-off-by: Jaegeuk Kim

f2fs: clarify and enhance the f2fs_gc flow

2013-02-11T22:15:02Z

This patch makes clearer the ambiguous f2fs_gc flow as follows. 1. Remove intermediate checkpoint condition during f2fs_gc (i.e., should_do_checkpoint() and GC_BLOCKED) 2. Remove unnecessary return values of f2fs_gc because of #1. (i.e., GC_NODE, GC_OK, etc) 3. Simplify write_checkpoint() because of #2. 4. Clarify the main f2fs_gc flow. o monitor how many freed sections during one iteration of do_garbage_collect(). o do GC more without checkpoints if we can't get enough free sections. o do checkpoint once we've got enough free sections through forground GCs. 5. Adopt thread-logging (Slack-Space-Recycle) scheme more aggressively on data log types. See. get_ssr_segement() Signed-off-by: Jaegeuk Kim

f2fs: remove repeated F2FS_SET_SB_DIRT call

2013-02-11T22:15:01Z

F2FS_SET_SB_DIRT is called in inc_page_count and it is directly called one more time in the next line. Signed-off-by: Changman Lee Signed-off-by: Jaegeuk Kim

f2fs: clean up the add_orphan_inode func

2013-02-11T22:15:00Z

For the code > prev = list_entry(orphan->list.prev, typeof(*prev), list); if orphan->list.prev == head, it can't get the right prev. And we can use the parameter 'this' to add. Signed-off-by: Jianpeng Ma Signed-off-by: Jaegeuk Kim

f2fs: prevent checkpoint once any IO failure is detected

2013-02-11T22:15:00Z

This patch enhances the checkpoint routine to cope with IO errors. Basically f2fs detects IO errors from end_io_write, and the errors are able to be occurred during one of data, node, and meta page writes. In the previous code, when an IO error is occurred during writes, f2fs sets a flag, CP_ERROR_FLAG, in the raw ckeckpoint buffer which will be written to disk. Afterwards, write_checkpoint() will check the flag and remount f2fs as a read-only (ro) mode. However, even once f2fs is remounted as a ro mode, dirty checkpoint pages are freely able to be written to disk by flusher or kswapd in background. In such a case, after cold reboot, f2fs would restore the checkpoint data having CP_ERROR_FLAG, resulting in disabling write_checkpoint and remounting f2fs as a ro mode again. Therefore, let's prevent any checkpoint page (meta) writes once an IO error is occurred, and remount f2fs as a ro mode right away at that moment. Reported-by: Oliver Winker Signed-off-by: Jaegeuk Kim Reviewed-by: Namjae Jeon