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2011-07-04UBIFS: re-arrange debugging code a bitArtem Bityutskiy
Move 'dbg_debugfs_init()' and 'dbg_debugfs_exit()' functions which initialize debugfs for whole UBIFS subsystem below the code which initializes debugfs for a particular UBIFS instance. And do the same for 'ubifs_debugging_init()' and 'ubifs_debugging_exit()' functions. This layout is a bit better for the next patches, so this is just a preparation. Also, rename 'open_debugfs_file()' into 'dfs_file_open()' for consistency. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-07-04UBIFS: be more informative in failure modeArtem Bityutskiy
When we are testing UBIFS recovery, it is better to print in which eraseblock we are going to fail. Currently UBIFS prints it only if recovery debugging messages are enabled, but this is not very practical. So change 'dbg_rcvry()' messages to 'ubifs_warn()' messages. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-07-04UBIFS: switch self-check knobs to debugfsArtem Bityutskiy
UBIFS has many built-in self-check functions which can be enabled using the debug_chks module parameter or the corresponding sysfs file (/sys/module/ubifs/parameters/debug_chks). However, this is not flexible enough because it is not per-filesystem. This patch moves this to debugfs interfaces. We already have debugfs support, so this patch just adds more debugfs files. While looking at debugfs support I've noticed that it is racy WRT file-system unmount, and added a TODO entry for that. This problem has been there for long time and it is quite standard debugfs PITA. The plan is to fix this later. This patch is simple, but it is large because it changes many places where we check if a particular type of checks is enabled or disabled. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-07-04UBIFS: lessen amount of debugging check typesArtem Bityutskiy
We have too many different debugging checks - lessen the amount by merging all index-related checks into one. At the same time, move the "force in-the-gap" test to the "index checks" class, because it is too heavy for the "general" class. This patch merges TNC, Old index, and Index size check and calles this just "index checks". Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-07-04UBIFS: introduce helper functions for debugging checks and testsArtem Bityutskiy
This patch introduces helper functions for all debugging checks, so instead of doing if (!(ubifs_chk_flags & UBIFS_CHK_GEN)) we now do if (!dbg_is_chk_gen(c)) This is a preparation to further changes where the flags will go away, and we'll need to only change the helper functions, but the code which utilizes them won't be touched. At the same time this patch removes 'dbg_force_in_the_gaps()', 'dbg_force_in_the_gaps_enabled()', and dbg_failure_mode helpers for consistency. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-07-04UBIFS: amend debugging inode size check function prototypeArtem Bityutskiy
Add 'const struct ubifs_info *c' parameter to 'dbg_check_synced_i_size()' function because we'll need it in the next patch when we switch to debugfs. So this patch is just a preparation. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-07-04UBIFS: amend debugging name check function prototypeArtem Bityutskiy
Add 'struct ubifs_info *c' parameter to the 'dbg_check_name()' debugging function - it will be needed in one of the following commits where we switch to debugfs. So this is just a preparation. Mark parameters as 'const' while on it. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-07-04UBIFS: add few commentaries about TNCArtem Bityutskiy
Add a couple of comments - while looking into TNC I could not easily figure out few facts, so it is a good idea to document them in the code. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-07-04UBIFS: use correct flags in lpropsArtem Bityutskiy
The UBIFS lpt tree is in many aspects similar to the TNC tree, and we have similar flags for these trees. And by mistake we use the COW_ZNODE flag for LPT in some places, instead of the right flag COW_CNODE. And this works only because these two constants have the same value. This patch makes all the LPT code to use COW_CNODE and also changes COW_CNODE constant value to make sure we do not misuse the flags any more. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-07-04UBIFS: harmonize znode flag helpersArtem Bityutskiy
We have 3 znode flags: cow, obsolete, dirty. For the last flag we have a 'ubifs_zn_dirty()' helper function, but for the other 2 flags we use 'test_bit()' directly. This patch makes the situation more consistent and introduces helpers for the other 2 flags: 'ubifs_zn_cow()' and 'ubifs_zn_obsolete()'. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-07-04UBIFS: remove dead codeArtem Bityutskiy
Remove dead pieces of code under "if (c->min_io_size == 1)" statement - we never execute it because in UBIFS 'c->min_io_size' is always at least 8. This are leftovers from old pre-mainline prototype. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-07-04UBIFS: remove unnecessary bracketsArtem Bityutskiy
Remove unnecessary brackets in "inode->i_flags |= (S_NOCMTIME)" statement to make the code not look silly. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-07-04UBIFS: minor cleanup: use S_ISREG helperArtem Bityutskiy
Instead of using long "(inode->i_mode & S_IFMT) != S_IFREG" expression, use shorted "!S_ISREG(inode->i_mode)". Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-07-04UBIFS: rename dbg_check_dir_size functionArtem Bityutskiy
Since this function is not only about size checking, rename it to 'dbg_check_dir()'. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-07-04UBIFS: improve inode dumping functionArtem Bityutskiy
Teach 'dbg_dump_inode()' dump directory entries for directory inodes. This requires few additional changes: 1. The 'c' argument of 'dbg_dump_inode()' cannot be const any more. 2. Users of 'dbg_dump_inode()' should not have 'tnc_mutex' locked. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-07-04UBIFS: dump stack when pnode or nnode reading failsArtem Bityutskiy
When we fail to read a pnode or nnode - print stacktrace if debugging is enabled. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-07-04UBIFS: lessen the size of debugging info data structureArtem Bityutskiy
This patch lessens the 'struct ubifs_debug_info' size by 90 bytes by allocating less bytes for the debugfs root directory name. It introduces macros for the name patter an length instead of hard-coding 100 bytes. It also makes UBIFS use 'snprintf()' and teaches it to gracefully catch situations when the name array is too short. Additionally, this patch makes 2 unrelated changes - I just thought they do not deserve separate commits: simplifies 'ubifs_assert()' for non-debugging case and makes 'dbg_debugfs_init()' properly verify debugfs return code which may be an error code or NULL, so we should you 'IS_ERR_OR_NULL()' instead of 'IS_ERR()'. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-07-04UBIFS: return EROFS in case of broken commitArtem Bityutskiy
If commit failed and it is in broken state, UBIFS switches to R/O mode. Most operations return -EROFS in this case, except of commit which returns -EINVAL. Make it return -EROFS too for consistency. This is also important for our power cut emulation testing. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-06-20ubifs: dereferencing an ERR_PTR in ubifs_mount()Dan Carpenter
d251ed271d5 "ubifs: fix sget races" left out the goto from this error path so the static checkers complain that we're dereferencing "sb" when it's an ERR_PTR. Signed-off-by: Dan Carpenter <error27@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-06-12ubifs: fix sget racesAl Viro
* allocate ubifs_info in ->mount(), fill it enough for sb_test() and set ->s_fs_info to it in set() callback passed to sget(). * do *not* free it in ->put_super(); do that in ->kill_sb() after we'd done kill_anon_super(). * don't free it in ubifs_fill_super() either - deactivate_locked_super() done by caller when ubifs_fill_super() returns an error will take care of that sucker. * get rid of kludge with passing ubi to ubifs_fill_super() in ->s_fs_info; we only need it in alloc_ubifs_info(), so ubifs_fill_super() will need only ubifs_info. Which it will find in ->s_fs_info just fine, no need to reassign anything... As the result, sb_test() becomes safe to apply to all superblocks that can be found by sget() (and a kludge with temporary use of ->s_fs_info to store a pointer to very different structure goes away). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-06-12ubifs: split allocation of ubifs_info into a separate functionAl Viro
preparation to ubifs sget() race fixes Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-06-03UBIFS: fix-up free space earlierBen Gardiner
The free space fixup is currently initiated during mount after the call to ubifs_write_master() which results in a write to PEBs; this has been observed with the patch 'assert no fixup when writing a node' applied: Move the free space fixup on mount to before the calls to ubifs_recover_inl_heads() and ubifs_write_master(). This results in no assertions with the previously mentioned patch applied. Artem: tweaked the patch a bit Signed-off-by: Ben Gardiner <bengardiner@nanometrics> Reviewed-by: Matthew L. Creech <mlcreech@gmail.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-06-03UBIFS: intialize LPT earlierBen Gardiner
The current 'mount_ubifs()' implementation does not initialize the LPT until the the master node is marked dirty. Move the LPT initialization to before marking the master node dirty. This is a preparation for the next patch which will move the free-space-fixup check to before marking the master node dirty, because we have to fix-up the free space before doing any writes. Artem: massaged the patch and commit message. Signed-off-by: Ben Gardiner <bengardiner@nanometrics.ca> Reviewed-by: Matthew L. Creech <mlcreech@gmail.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-06-03UBIFS: assert no fixup when writing a nodeBen Gardiner
The current free space fixup can result in some writing to the UBI volume when the space_fixup flag is set. To catch instances where UBIFS is writing to the NAND while the space_fixup flag is set, add an assert to ubifs_write_node(). Artem: tweaked the patch, added similar assertion to the write buffer write path. Signed-off-by: Ben Gardiner <bengardiner@nanometrics.ca> Reviewed-by: Matthew L. Creech <mlcreech@gmail.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-06-03UBIFS: fix clean znode counter corruption in error casesArtem Bityutskiy
UBIFS maintains per-filesystem and global clean znode counters ('c->clean_zn_cnt' and 'ubifs_clean_zn_cnt'). It is important to maintain correct values there since the shrinker relies on 'ubifs_clean_zn_cnt'. However, in case of failures during commit the counters were corrupted. E.g., if a failure happens in the middle of 'write_index()', then some nodes in the commit list ('c->cnext') are marked as clean, and some are marked as dirty. And the 'ubifs_destroy_tnc_subtree()' frees does not retrun correct count, and we end up with non-zero 'c->clean_zn_cnt' when unmounting. This means that if we have 2 file-sytem and one of them fails, and we unmount it, 'ubifs_clean_zn_cnt' stays incorrect and confuses the shrinker. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-06-03UBIFS: fix memory leak on error pathArtem Bityutskiy
UBIFS leaks memory on error path in 'ubifs_jnl_update()' in case of write failure because it forgets to free the 'struct ubifs_dent_node *dent' object. Although the object is small, the alignment can make it large - e.g., 2KiB if the min. I/O unit is 2KiB. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Cc: stable@kernel.org
2011-06-03UBIFS: fix shrinker object count reportsArtem Bityutskiy
Sometimes VM asks the shrinker to return amount of objects it can shrink, and we return the ubifs_clean_zn_cnt in that case. However, it is possible that this counter is negative for a short period of time, due to the way UBIFS TNC code updates it. And I can observe the following warnings sometimes: shrink_slab: ubifs_shrinker+0x0/0x2b7 [ubifs] negative objects to delete nr=-8541616642706119788 This patch makes sure UBIFS never returns negative count of objects. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Cc: stable@kernel.org
2011-06-01UBIFS: fix recovery broken by the previous recovery fixArtem Bityutskiy
Unfortunately, the recovery fix d1606a59b6be4ea392eabd40d1250aa1eeb19efb (UBIFS: fix extremely rare mount failure) broke recovery. This commit make UBIFS drop the last min. I/O unit in all journal heads, but this is needed only for the GC head. And this does not work for non-GC heads. For example, if suppose we have min. I/O units A and B, and A contains a valid node X, which was fsynced, and then a group of nodes Y which spans the rest of A and B. In this case we'll drop not only Y, but also X, which is obviously incorrect. This patch fixes the issue and additionally makes recovery to drop last min. I/O unit only for the GC head, and leave things as they have been for ages for the other heads - this is safer. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-06-01UBIFS: amend ubifs_recover_leb interfaceArtem Bityutskiy
Instead of passing "grouped" parameter to 'ubifs_recover_leb()' which tells whether the nodes are grouped in the LEB to recover, pass the journal head number and let 'ubifs_recover_leb()' look at the journal head's 'grouped' flag. This patch is a preparation to a further fix where we'll need to know the journal head number for other purposes. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-06-01UBIFS: introduce a "grouped" journal head flagArtem Bityutskiy
Journal heads are different in a way how UBIFS writes nodes there. All normal journal heads receive grouped nodes, while the GC journal heads receives ungrouped nodes. This patch adds a 'grouped' flag to 'struct ubifs_jhead' which describes this property. This patch is a preparation to a further recovery fix. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-06-01UBIFS: supress false error messagesArtem Bityutskiy
Commit ab51afe05273741f72383529ef488aa1ea598ec6 was a good clean-up, but it introduced a regression - now UBIFS prints scary error messages during recovery on all corrupted nodes, even though the corruptions are expected (due to a power cut). This patch fixes the issue. Additionally fix a typo in a commentary introduced by the same commit. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-05-29cifs/ubifs: Fix shrinker API change falloutAl Viro
Commit 1495f230fa77 ("vmscan: change shrinker API by passing shrink_control struct") changed the API of ->shrink(), but missed ubifs and cifs instances. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-28ubifs: remove unnecessary dentry_unhash from rmdir, dir renameSage Weil
ubifs does not have problems with references to unlinked directories. CC: Artem Bityutskiy <dedekind1@gmail.com> CC: Adrian Hunter <adrian.hunter@nokia.com> CC: linux-mtd@lists.infradead.org Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-05-27fs: pass exact type of data dirties to ->dirty_inodeChristoph Hellwig
Tell the filesystem if we just updated timestamp (I_DIRTY_SYNC) or anything else, so that the filesystem can track internally if it needs to push out a transaction for fdatasync or not. This is just the prototype change with no user for it yet. I plan to push large XFS changes for the next merge window, and getting this trivial infrastructure in this window would help a lot to avoid tree interdependencies. Also remove incorrect comments that ->dirty_inode can't block. That has been changed a long time ago, and many implementations rely on it. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-05-26Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (25 commits) cifs: remove unnecessary dentry_unhash on rmdir/rename_dir ocfs2: remove unnecessary dentry_unhash on rmdir/rename_dir exofs: remove unnecessary dentry_unhash on rmdir/rename_dir nfs: remove unnecessary dentry_unhash on rmdir/rename_dir ext2: remove unnecessary dentry_unhash on rmdir/rename_dir ext3: remove unnecessary dentry_unhash on rmdir/rename_dir ext4: remove unnecessary dentry_unhash on rmdir/rename_dir btrfs: remove unnecessary dentry_unhash in rmdir/rename_dir ceph: remove unnecessary dentry_unhash calls vfs: clean up vfs_rename_other vfs: clean up vfs_rename_dir vfs: clean up vfs_rmdir vfs: fix vfs_rename_dir for FS_RENAME_DOES_D_MOVE filesystems libfs: drop unneeded dentry_unhash vfs: update dentry_unhash() comment vfs: push dentry_unhash on rename_dir into file systems vfs: push dentry_unhash on rmdir into file systems vfs: remove dget() from dentry_unhash() vfs: dentry_unhash immediately prior to rmdir vfs: Block mmapped writes while the fs is frozen ...
2011-05-26vfs: push dentry_unhash on rename_dir into file systemsSage Weil
Only a few file systems need this. Start by pushing it down into each rename method (except gfs2 and xfs) so that it can be dealt with on a per-fs basis. Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-05-26vfs: push dentry_unhash on rmdir into file systemsSage Weil
Only a few file systems need this. Start by pushing it down into each fs rmdir method (except gfs2 and xfs) so it can be dealt with on a per-fs basis. This does not change behavior for any in-tree file systems. Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-05-23UBIFS: switch to dynamic printksArtem Bityutskiy
Switch to debugging using dynamic printk (pr_debug()). There is no good reason to carry custom debugging prints if there is so cool and powerful generic dynamic printk infrastructure, see Documentation/dynamic-debug-howto.txt. With dynamic printks we can switch on/of individual prints, per-file, per-function and per format messages. This means that instead of doing old-fashioned echo 1 > /sys/module/ubifs/parameters/debug_msgs to enable general messages, we can do: echo 'format "UBIFS DBG gen" +ptlf' > control to enable general messages and additionally ask the dynamic printk infrastructure to print process ID, line number and function name. So there is no reason to keep UBIFS-specific crud if there is more powerful generic thing. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-05-20UBIFS: fix kernel-doc commentsArtem Bityutskiy
This is a minor fix for UBIFS kernel-doc comments - we forgot the "@" symbol for several 'struct ubifs_debug_info'. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-05-16UBIFS: fix extremely rare mount failureArtem Bityutskiy
This patch fixes an extremely rare mount failure after a power cut, when mount fails with ENOSPC error because UBIFS could not find the GC LEB. In short, the reason for this failure is that after recovery the GC head LEB contains less free space than it had contained just before the power cut happened. As a result, if the FS is full, 'ubifs_rcvry_gc_commit()' is unable to find a dirty LEB to GC and a free LEB, so mount fails. This patch contains a huge comment with more detailed explanation, please refer that comment. Since this is really really rare and unlikely situation, I do not send this patch to the stable tree, also because it requires a lot of preparation patches which I did before. So sending this to -stable would be too risky. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-05-16UBIFS: simplify LEB recovery function furtherArtem Bityutskiy
Further simplify 'ubifs_recover_leb()' by noticing that we have to call 'clean_buf()' in any case, and it is fine to call it if the offset is aligned to 'c->min_io_size'. Thus, we do not have to call it separately from every "if" - just call it once at the end. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-05-16UBIFS: always cleanup the recovered LEBArtem Bityutskiy
Now when we call 'ubifs_recover_leb()' only for LEBs which are potentially corrupted (i.e., only for last buds, not for all of them), we can cleanup every LEB, not only those where we find corruption. The reason - unstable bits. Even though the LEB may look good now, it might contain unstable bits which may hit us a bit later. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-05-16UBIFS: clean up LEB recovery functionArtem Bityutskiy
This patch cleans up 'ubifs_recover_leb()' function and makes it more readable. Move things which are done only once out of the loop and kill unneeded 'switch' statement. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-05-16UBIFS: fix-up free space on mount if flag is setMatthew L. Creech
If a UBIFS filesystem is being mounted read-write, or is being remounted from read-only to read-write, check for the "space_fixup" flag and fix all LEBs containing empty space if necessary. Artem: tweaked the patch a bit Signed-off-by: Matthew L. Creech <mlcreech@gmail.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-05-16UBIFS: add the fixup functionMatthew L. Creech
This patch adds the 'ubifs_fixup_free_space()' function which scans all LEBs in the filesystem for those that are in-use but have one or more empty pages, then re-maps the LEBs in order to erase the empty portions. Afterward it removes the "space_fixup" flag from the UBIFS superblock. Artem: massaged the patch Signed-off-by: Matthew L. Creech <mlcreech@gmail.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-05-16UBIFS: add a superblock flag for free space fix-upMatthew L. Creech
The 'space_fixup' flag can be set in the superblock of a new filesystem by mkfs.ubifs to indicate that any eraseblocks with free space remaining should be fixed-up the first time it's mounted (after which the flag is un-set). This means that the UBIFS image has been flashed by a "dumb" flasher and the free space has been actually programmed (writing all 0xFFs), so this free space cannot be used. UBIFS fixes the free space up by re-writing the contents of all LEBs with free space using the atomic LEB change UBI operation. Artem: improved commit message, add some more commentaries to the code. Signed-off-by: Matthew L. Creech <mlcreech@gmail.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-05-16UBIFS: share the next_log_lnum helperArtem Bityutskiy
We'll need to use the 'next_log_lnum()' helper function from log.c in the fixup code, so let's move it to misc.h. IOW, this is a preparation to the following free space fixup changes. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-05-16UBIFS: expect corruption only in last journal head LEBsArtem Bityutskiy
This patch improves UBIFS recovery and teaches it to expect corruption only in the last buds. Indeed, currently we just recover all buds, which is incorrect because only the last buds can have corruptions in case of a power cut. So it is inconsistent with the rest of the recovery strategy which tries hard to distinguish between corruptions cause by power cuts and other types of corruptions. This patch also adds one quirk - a bit older UBIFS was could have corruption in the next to last bud because of the way it switched buds: when bud A is full, it first searched for the next bud B, the wrote a reference node to the log about B, and then synchronized the write-buffer of A. So we could end up with buds A and B, where B is the last, but A had corruption. The UBIFS behavior was fixed, though, so currently it always first synchronizes A's write-buffer and only after this adds B to the log. However, to be make sure that we handle unclean (after a power cut) UBIFS images belonging to older UBIFS - we need to add a quirk and keep it for some time: we need to check for the situation described above. Thankfully, it is easy to check for that situation. When UBIFS adds B to the log, it always first unmaps B, then maps it, and then syncs A's write-buffer. Thus, in that situation we can check that B is empty, in which case it is OK to have corruption in A. To check that B is empty it is enough to just read the first few bytes of the bud and compare them with 0xFFs. This quirk may be removed in a couple of years. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-05-16UBIFS: synchronize write-buffer before switching to the next budArtem Bityutskiy
Currently when UBIFS fills up the current bud (which is the last in the journal head) and switches to the next bud, it first writes the log reference node for the next bud and only after this synchronizes the write-buffer of the previous bud. This is not a big deal, but an unclean power cut may lead to a situation when we have corruption in a next-to-last bud, although it is much more logical that we have to have corruption only in the last bud. This patch also removes write-buffer synchronization from 'ubifs_wbuf_seek_nolock()' because this is not needed anymore (we synchronize the write-buffer explicitly everywhere now) and also because this is just prone to various errors. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-05-16UBIFS: remove BUG statementArtem Bityutskiy
Remove a 'BUG()' statement when we are unable to find a bud and add a similar 'ubifs_assert()' statement instead. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>