kernel.git/fs/nilfs2/segment.c, branch linux-2.6.30.y

nilfs2: fix oops due to inconsistent state in page with discrete b-tree nodes

2009-08-16T21:18:34Z

commit a97778457f22181e8c38c4cd7d7e528378738a98 upstream. Andrea Gelmini gave me a report that a kernel oops hit on a nilfs filesystem with a 1KB block size when doing rsync. This turned out to be caused by an inconsistency of dirty state between a page and its buffers storing b-tree node blocks. If the page had multiple buffers split over multiple logs, and if the logs were written at a time, a dirty flag remained in the page even every dirty flag in the buffers was cleared. This will fix the failure by dropping the dirty flag properly for pages with the discrete multiple b-tree nodes. Reported-by: Andrea Gelmini Signed-off-by: Ryusuke Konishi Tested-by: Andrea Gelmini Signed-off-by: Greg Kroah-Hartman

nilfs2: fix hang problem of log writer which occurs after write failures

2009-07-30T21:39:48Z

commit 8227b29722fdbac72357aae155d171a5c777670c upstream. Leandro Lucarella gave me a report that nilfs gets stuck after its write function fails. The problem turned out to be caused by bugs which leave writeback flag on pages. This fixes the problem by ensuring to clear the writeback flag in error path. Reported-by: Leandro Lucarella Signed-off-by: Ryusuke Konishi Signed-off-by: Greg Kroah-Hartman

nilfs2: remove unlikely directive causing mis-conversion of error code

2009-07-30T21:39:47Z

commit 0cfae3d8795f388f9de78adb0171520d19da77e9 upstream. The following error code handling in nilfs_segctor_write() function wrongly converted negative error codes to a truth value (i.e. 1): err = unlikely(err) ? : res; which originaly meant to be err = err ? : res; This mis-conversion caused that write or sync functions receive the unexpected error code. This fixes the bug by removing the unlikely directive. Signed-off-by: Ryusuke Konishi Signed-off-by: Greg Kroah-Hartman

nilfs2: fix lock order reversal in nilfs_clean_segments ioctl

2009-05-11T05:54:41Z

This is a companion patch to ("nilfs2: fix possible circular locking for get information ioctls"). This corrects lock order reversal between mm->mmap_sem and nilfs->ns_segctor_sem in nilfs_clean_segments() which was detected by lockdep check: ======================================================= [ INFO: possible circular locking dependency detected ] 2.6.30-rc3-nilfs-00003-g360bdc1 #7 ------------------------------------------------------- mmap/5294 is trying to acquire lock: (&nilfs->ns_segctor_sem){++++.+}, at: [] nilfs_transaction_begin+0xb6/0x10c [nilfs2] but task is already holding lock: (&mm->mmap_sem){++++++}, at: [] do_page_fault+0x1d8/0x30a which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&mm->mmap_sem){++++++}: [] __lock_acquire+0x1066/0x13b0 [] lock_acquire+0xba/0xdd [] might_fault+0x68/0x88 [] copy_from_user+0x2a/0x111 [] nilfs_ioctl_prepare_clean_segments+0x1d/0xf1 [nilfs2] [] nilfs_clean_segments+0x6d/0x1b9 [nilfs2] [] nilfs_ioctl+0x2ad/0x318 [nilfs2] [] vfs_ioctl+0x22/0x69 [] do_vfs_ioctl+0x460/0x499 [] sys_ioctl+0x40/0x5a [] sysenter_do_call+0x12/0x38 [] 0xffffffff -> #0 (&nilfs->ns_segctor_sem){++++.+}: [] __lock_acquire+0xdcc/0x13b0 [] lock_acquire+0xba/0xdd [] down_read+0x2a/0x3e [] nilfs_transaction_begin+0xb6/0x10c [nilfs2] [] nilfs_page_mkwrite+0xe7/0x154 [nilfs2] [] __do_fault+0x165/0x376 [] handle_mm_fault+0x287/0x5d1 [] do_page_fault+0x2fb/0x30a [] error_code+0x72/0x78 [] 0xffffffff where nilfs_clean_segments() holds: nilfs->ns_segctor_sem -> copy_from_user() --> page fault -> mm->mmap_sem And, page fault path may hold: page fault -> mm->mmap_sem --> nilfs_page_mkwrite() -> nilfs->ns_segctor_sem Even though nilfs_clean_segments() does not perform write access on given user pages, it may cause deadlock because nilfs->ns_segctor_sem is shared per device and mm->mmap_sem can be shared with other tasks. To avoid this problem, this patch moves all calls of copy_from_user() outside the nilfs->ns_segctor_sem lock in the ioctl. Signed-off-by: Ryusuke Konishi

nilfs2: introduce secondary super block

2009-04-07T15:31:20Z

The former versions didn't have extra super blocks. This improves the weak point by introducing another super block at unused region in tail of the partition. This doesn't break disk format compatibility; older versions just ingore the secondary super block, and new versions just recover it if it doesn't exist. The partition created by an old mkfs may not have unused region, but in that case, the secondary super block will not be added. This doesn't make more redundant copies of the super block; it is a future work. Signed-off-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

nilfs2: simplify handling of active state of segments

2009-04-07T15:31:20Z

will reduce some lines of segment constructor. Previously, the state was complexly controlled through a list of segments in order to keep consistency in meta data of usage state of segments. Instead, this presents ``calculated'' active flags to userland cleaner program and stop maintaining its real flag on disk. Only by this fake flag, the cleaner cannot exactly know if each segment is reclaimable or not. However, the recent extension of nilfs_sustat ioctl struct (nilfs2-extend-nilfs_sustat-ioctl-struct.patch) can prevent the cleaner from reclaiming in-use segment wrongly. So, now I can apply this for simplification. Signed-off-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

nilfs2: mark minor flag for checkpoint created by internal operation

2009-04-07T15:31:19Z

Nilfs creates checkpoints even for garbage collection or metadata updates such as checkpoint mode change. So, user often sees checkpoints created only by such internal operations. This is inconvenient in some situations. For example, application that monitors checkpoints and changes them to snapshots, will fall into an infinite loop because it cannot distinguish internally created checkpoints. This patch solves this sort of problem by adding a flag to checkpoint for identification. Signed-off-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

nilfs2: clean up sketch file

2009-04-07T15:31:19Z

The sketch file is a file to mark checkpoints with user data. It was experimentally introduced in the original implementation, and now obsolete. The file was handled differently with regular files; the file size got truncated when a checkpoint was created. This stops the special treatment and will treat it as a regular file. Most users are not affected because mkfs.nilfs2 no longer makes this file. Signed-off-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

nilfs2: replace BUG_ON and BUG calls triggerable from ioctl

2009-04-07T15:31:19Z

Pekka Enberg advised me: > It would be nice if BUG(), BUG_ON(), and panic() calls would be > converted to proper error handling using WARN_ON() calls. The BUG() > call in nilfs_cpfile_delete_checkpoints(), for example, looks to be > triggerable from user-space via the ioctl() system call. This will follow the comment and keep them to a minimum. Acked-by: Pekka Enberg Signed-off-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

nilfs2: extend nilfs_sustat ioctl struct

2009-04-07T15:31:19Z

This adds a new argument to the nilfs_sustat structure. The extended field allows to delete volatile active state of segments, which was needed to protect freshly-created segments from garbage collection but has confused code dealing with segments. This extension alleviates the mess and gives room for further simplifications. The volatile active flag is not persistent, so it's eliminable on this occasion without affecting compatibility other than the ioctl change. Signed-off-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds