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2013-02-12f2fs: clarify and enhance the f2fs_gc flowJaegeuk Kim1-2/+19
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 <jaegeuk.kim@samsung.com>
2013-02-12f2fs: prevent checkpoint once any IO failure is detectedJaegeuk Kim1-6/+2
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 <oliver@oli1170.net> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com> Reviewed-by: Namjae Jeon <namjae.jeon@samsung.com>
2013-01-10f2fs: revisit the f2fs_gc flowJaegeuk Kim1-1/+1
I'd like to revisit the f2fs_gc flow and rewrite as follows. 1. In practical, the nGC parameter of f2fs_gc is meaningless. So, let's remove it. 2. Background GC marks victim blocks as dirty one at a time. 3. Foreground GC should do cleaning job until acquiring enough free sections. Afterwards, it needs to do checkpoint. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2012-12-28f2fs: remove unneeded initialization of nr_dirty in dirty_seglist_infoNamjae Jeon1-1/+0
Since, the memory for the object of dirty_seglist_info is allocated using kzalloc - which returns zeroed out memory. So, there is no need to initialize the nr_dirty values with zeroes. 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>
2012-12-28f2fs: fix equation of has_not_enough_free_secs()Jaegeuk Kim1-34/+2
Practically, has_not_enough_free_secs() should calculate with the numbers of current node and directory data blocks together. Actually the equation was implemented in need_to_flush(). So, this patch removes need_flush() and moves the equation into has_not_enough_free_secs(). Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2012-12-28f2fs: return a default value for non-void functionJaegeuk Kim1-4/+3
This patch resolves a build warning reported by kbuild test robot. " fs/f2fs/segment.c: In function '__get_segment_type': fs/f2fs/segment.c:806:1: warning: control reaches end of non-void function [-Wreturn-type] " Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2012-12-28f2fs: add missing #include <linux/prefetch.h>Geert Uytterhoeven1-0/+1
m68k allmodconfig: fs/f2fs/data.c: In function ‘read_end_io’: fs/f2fs/data.c:311: error: implicit declaration of function ‘prefetchw’ fs/f2fs/segment.c: In function ‘f2fs_end_io_write’: fs/f2fs/segment.c:628: error: implicit declaration of function ‘prefetchw’ Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2012-12-26f2fs: remove set_page_dirty for atomic f2fs_end_io_writeJaegeuk Kim1-1/+0
We should guarantee not to do *scheduling while atomic*. I found, in atomic f2fs_end_io_write(), there is a set_page_dirty() call to deal with IO errors. But, set_page_dirty() calls: -> f2fs_set_data_page_dirty() -> set_dirty_dir_page() -> cond_resched() which results in scheduling. In order to avoid this, I'd like to remove simply set_page_dirty(), since the page is already marked as ERROR and f2fs will be operated as the read-only mode as well. So, there is no recovery issue with this. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2012-12-11f2fs: cleanup the f2fs_bio_alloc routineJaegeuk Kim1-15/+18
Do cleanup more for better code readability. - Change the parameter set of f2fs_bio_alloc() This function should allocate a bio only since it is not something like f2fs_bio_init(). Instead, the caller should initialize the allocated bio. - Introduce SECTOR_FROM_BLOCK This macro translates a block address to its sector address. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com> Reviewed-by: Namjae Jeon <namjae.jeon@samsung.com>
2012-12-11f2fs: rewrite f2fs_bio_alloc to make it simplerNamjae Jeon1-17/+7
Since, GFP_NOFS(__GFP_WAIT) is used for allocation requests of bio in f2fs. So, there is no chance of returning NULL from the BIO allocation. Making the bio allocation routine for f2fs simpler. Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com> Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com>
2012-12-11f2fs: remove unneeded initializationNamjae Jeon1-2/+2
No need to initialize "struct f2fs_gc_kthread *gc_th = NULL", as gc_th = NULL, will be taken care by the return values of kmalloc(). And fix codes in other places. Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com> Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com>
2012-12-11f2fs: adjust kernel coding styleJaegeuk Kim1-13/+13
As pointed out by Randy Dunlap, this patch removes all usage of "/**" for comment blocks. Instead, just use "/*". Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2012-12-11f2fs: fix endian conversion bugs reported by sparseJaegeuk Kim1-7/+7
This patch should resolve the bugs reported by the sparse tool. Initial reports were written by "kbuild test robot" managed by fengguang.wu. In my local machines, I've tested also by running: > make C=2 CF="-D__CHECK_ENDIAN__" Accordingly, I've found lots of warnings and bugs related to the endian conversion. And I've fixed all at this moment. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2012-12-11f2fs: add segment operationsJaegeuk Kim1-0/+1798
This adds specific functions not only to manage dirty/free segments, SIT pages, a cache for SIT entries, and summary entries, but also to allocate free blocks and write three types of pages: data, node, and meta. - F2FS maintains three types of bitmaps in memory, which indicate free, prefree, and dirty segments respectively. - The key information of an SIT entry consists of a segment number, the number of valid blocks in the segment, a bitmap to identify there-in valid or invalid blocks. - An SIT page is composed of a certain range of SIT entries, which is maintained by the address space of meta_inode. - To cache SIT entries, a simple array is used. The index for the array is the segment number. - A summary entry for data contains the parent node information. A summary entry for node contains its node offset from the inode. - F2FS manages information about six active logs and those summary entries in memory. Whenever one of them is changed, its summary entries are flushed to its SIT page maintained by the address space of meta_inode. - This patch adds a default block allocation function which supports heap-based allocation policy. - This patch adds core functions to write data, node, and meta pages. Since LFS basically produces a series of sequential writes, F2FS merges sequential bios with a single one as much as possible to reduce the IO scheduling overhead. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>