kernel.git/fs/nilfs2/super.c, branch linux-3.4.y

nilfs2: fix deadlock issue between chcp and thaw ioctls

2012-08-15T15:10:05Z

commit 572d8b3945a31bee7c40d21556803e4807fd9141 upstream. An fs-thaw ioctl causes deadlock with a chcp or mkcp -s command: chcp D ffff88013870f3d0 0 1325 1324 0x00000004 ... Call Trace: nilfs_transaction_begin+0x11c/0x1a0 [nilfs2] wake_up_bit+0x20/0x20 copy_from_user+0x18/0x30 [nilfs2] nilfs_ioctl_change_cpmode+0x7d/0xcf [nilfs2] nilfs_ioctl+0x252/0x61a [nilfs2] do_page_fault+0x311/0x34c get_unmapped_area+0x132/0x14e do_vfs_ioctl+0x44b/0x490 __set_task_blocked+0x5a/0x61 vm_mmap_pgoff+0x76/0x87 __set_current_blocked+0x30/0x4a sys_ioctl+0x4b/0x6f system_call_fastpath+0x16/0x1b thaw D ffff88013870d890 0 1352 1351 0x00000004 ... Call Trace: rwsem_down_failed_common+0xdb/0x10f call_rwsem_down_write_failed+0x13/0x20 down_write+0x25/0x27 thaw_super+0x13/0x9e do_vfs_ioctl+0x1f5/0x490 vm_mmap_pgoff+0x76/0x87 sys_ioctl+0x4b/0x6f filp_close+0x64/0x6c system_call_fastpath+0x16/0x1b where the thaw ioctl deadlocked at thaw_super() when called while chcp was waiting at nilfs_transaction_begin() called from nilfs_ioctl_change_cpmode(). This deadlock is 100% reproducible. This is because nilfs_ioctl_change_cpmode() first locks sb->s_umount in read mode and then waits for unfreezing in nilfs_transaction_begin(), whereas thaw_super() locks sb->s_umount in write mode. The locking of sb->s_umount here was intended to make snapshot mounts and the downgrade of snapshots to checkpoints exclusive. This fixes the deadlock issue by replacing the sb->s_umount usage in nilfs_ioctl_change_cpmode() with a dedicated mutex which protects snapshot mounts. Signed-off-by: Ryusuke Konishi Cc: Fernando Luis Vazquez Cao Tested-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

switch open-coded instances of d_make_root() to new helper

2012-03-21T01:29:35Z

Signed-off-by: Al Viro

vfs: check i_nlink limits in vfs_{mkdir,rename_dir,link}

2012-03-21T01:29:32Z

New field of struct super_block - ->s_max_links. Maximal allowed value of ->i_nlink or 0; in the latter case all checks still need to be done in ->link/->mkdir/->rename instances. Note that this limit applies both to directoris and to non-directories. Signed-off-by: Al Viro

vfs: switch ->show_options() to struct dentry *

2012-01-07T04:19:54Z

Signed-off-by: Al Viro

vfs: fix the stupidity with i_dentry in inode destructors

2012-01-04T03:52:40Z

Seeing that just about every destructor got that INIT_LIST_HEAD() copied into it, there is no point whatsoever keeping this INIT_LIST_HEAD in inode_init_once(); the cost of taking it into inode_init_always() will be negligible for pipes and sockets and negative for everything else. Not to mention the removal of boilerplate code from ->destroy_inode() instances... Signed-off-by: Al Viro

nilfs2: always set back pointer to host inode in mapping->host

2011-05-10T13:21:57Z

In the current nilfs, page cache for btree nodes and meta data files do not set a valid back pointer to the host inode in mapping->host. This will change it so that every address space in nilfs uses mapping->host to hold its host inode. Signed-off-by: Ryusuke Konishi

nilfs2: implement resize ioctl

2011-05-10T13:21:46Z

This adds resize ioctl which makes online resize possible. Signed-off-by: Ryusuke Konishi

nilfs2: add routine to move secondary super block

2011-05-10T13:21:45Z

After resizing the filesystem, the secondary super block must be moved to a new location. This adds a helper function for this. Signed-off-by: Ryusuke Konishi

nilfs2: get rid of nilfs_sb_info structure

2011-03-09T02:54:26Z

This directly uses sb->s_fs_info to keep a nilfs filesystem object and fully removes the intermediate nilfs_sb_info structure. With this change, the hierarchy of on-memory structures of nilfs will be simplified as follows: Before: super_block -> nilfs_sb_info -> the_nilfs -> cptree --+-> nilfs_root (current file system) +-> nilfs_root (snapshot A) +-> nilfs_root (snapshot B) : -> nilfs_sc_info (log writer structure) After: super_block -> the_nilfs -> cptree --+-> nilfs_root (current file system) +-> nilfs_root (snapshot A) +-> nilfs_root (snapshot B) : -> nilfs_sc_info (log writer structure) The reason why we didn't design so from the beginning is because the initial shape also differed from the above. The early hierachy was composed of "per-mount-point" super_block -> nilfs_sb_info pairs and a shared nilfs object. On the kernel 2.6.37, it was changed to the current shape in order to unify super block instances into one per device, and this cleanup became applicable as the result. Signed-off-by: Ryusuke Konishi

nilfs2: use sb instance instead of nilfs_sb_info struct

2011-03-09T02:05:08Z

This replaces sbi uses with direct reference to sb instance. Signed-off-by: Ryusuke Konishi