linux/fs/sysfs/dir.c, branch v3.4.19

sysfs: sysfs_pathname/sysfs_add_one: Use strlcat() instead of strcat()

2012-10-31T17:02:57Z

commit 66081a72517a131430dcf986775f3268aafcb546 upstream. The warning check for duplicate sysfs entries can cause a buffer overflow when printing the warning, as strcat() doesn't check buffer sizes. Use strlcat() instead. Since strlcat() doesn't return a pointer to the passed buffer, unlike strcat(), I had to convert the nested concatenation in sysfs_add_one() to an admittedly more obscure comma operator construct, to avoid emitting code for the concatenation if CONFIG_BUG is disabled. Signed-off-by: Geert Uytterhoeven Signed-off-by: Greg Kroah-Hartman

sysfs: handle 'parent deleted before child added'

2012-04-10T21:48:51Z

In scsi at least two cases of the parent device being deleted before the child is added have been observed. 1/ scsi is performing async scans and the device is removed prior to the async can thread running (can happen with an in-opportune / unlikely unplug during initial scan). 2/ libsas discovery event running after the parent port has been torn down (this is a bug in libsas). Result in crash signatures like: BUG: unable to handle kernel NULL pointer dereference at 0000000000000098 IP: [] sysfs_create_dir+0x32/0xb6 ... Process scsi_scan_8 (pid: 5417, threadinfo ffff88080bd16000, task ffff880801b8a0b0) Stack: 00000000fffffffe ffff880813470628 ffff88080bd17cd0 ffff88080614b7e8 ffff88080b45c108 00000000fffffffe ffff88080bd17d20 ffffffff8125e4a8 ffff88080bd17cf0 ffffffff81075149 ffff88080bd17d30 ffff88080614b7e8 Call Trace: [] kobject_add_internal+0x120/0x1e3 [] ? trace_hardirqs_on+0xd/0xf [] kobject_add_varg+0x41/0x50 [] kobject_add+0x64/0x66 [] device_add+0x12d/0x63a In this scenario the parent is still valid (because we have a reference), but it has been device_del()'d which means its kobj->sd pointer is NULL'd via: device_del()->kobject_del()->sysfs_remove_dir() ...and then sysfs_create_dir() (without this fix) goes ahead and de-references parent_sd via sysfs_ns_type(): return (sd->s_flags & SYSFS_NS_TYPE_MASK) >> SYSFS_NS_TYPE_SHIFT; This scenario is being fixed in scsi/libsas, but if other subsystems present the same ordering the system need not immediately crash. Cc: Greg Kroah-Hartman Cc: James Bottomley Signed-off-by: Dan Williams Signed-off-by: Greg Kroah-Hartman

sysfs: Update the name hash for an entry after changing the namespace

2012-04-09T22:33:00Z

This is needed to allow renaming network devices that have been moved to another network namespace. Signed-off-by: Tom Goff Signed-off-by: Greg Kroah-Hartman

Revert "sysfs: Kill nlink counting."

2012-03-08T21:03:10Z

This reverts commit 524b6c5b39b931311dfe5a2f5abae2f5c9731676. It has shown to break userspace tools, which is not acceptable. Reported-by: Jiri Slaby Cc: Eric W. Biederman Cc: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

sysfs: Update the name hash when renaming sysfs entries

2012-01-31T19:30:48Z

This fixes a bug introduced with sysfs name hashes where renaming a network device appears to succeed but silently makes the sysfs files for that network device inaccessible. In at least one configuration this bug has stopped networking from coming up during boot. Signed-off-by: Eric W. Biederman Tested-by: Jiri Slaby Signed-off-by: Greg Kroah-Hartman

sysfs: Kill nlink counting.

2012-01-24T20:41:46Z

Tracking the number of subdirectories requires an extra field that increases the size of sysfs_dirent. nlinks are not particularly interesting for sysfs and the nlink counts are wrong when network namespaces are involved so stop counting them, and always return nlink == 1. Userspace already knows that directories with nlink == 1 have an nlink count they can't use to count subdirectories. This reduces the size of sysfs_dirent by 8 bytes on 64bit platforms. Signed-off-by: Eric W. Biederman Signed-off-by: Greg Kroah-Hartman

sysfs: Store the sysfs inode in an unsigned int.

2012-01-24T20:41:46Z

Store the sysfs inode number in an unsided int because ida inode allocator can return at most a 31 bit number, reducing the size of struct sysfs_dirent by 8 bytes on 64bit platforms. Signed-off-by: Eric W. Biederman Signed-off-by: Greg Kroah-Hartman

sysfs: Add s_hash to sysfs_dirent and order directory entries by hash

2012-01-24T20:36:17Z

Compute a 31 bit hash of directory entries (that can fit in a signed 32bit off_t) and index the sysfs directory entries by that hash, replacing the per directory indexes by name and by inode. Because we now only use a single rbtree this reduces the size of sysfs_dirent by 2 pointers. Because we have fewer cases to deal with the code is now simpler. For now I use the simple hash that the dcache uses as that is easy to use and seems simple enough. In addition to makeing the code simpler using a hash for the file position in readdir brings sysfs in line with other filesystems that have non-trivial directory structures. Signed-off-by: Eric W. Biederman Signed-off-by: Greg Kroah-Hartman

sysfs: Make sysfs_rename safe with sysfs_dirents in rbtrees.

2011-11-01T16:16:14Z

In sysfs_rename we need to remove the optimization of not calling sysfs_unlink_sibling and sysfs_link_sibling if the renamed parent directory is not changing. This optimization is no longer valid now that sysfs dirents are stored in an rbtree sorted by name. Move the assignment of s_ns before the call of sysfs_link_sibling. With no sysfs_dirent fields changing after the call of sysfs_link_sibling this allows sysfs_link_sibling to take any of the directory entries into account when it builds the rbtrees, and s_ns looks like a prime canidate to be used in the rbtree in the future. Signed-off-by: Eric W. Biederman Cc: Jiri Slaby Cc: Greg KH Cc: David Miller Cc: Mikulas Patocka Cc: Andrew Morton Signed-off-by: Linus Torvalds

sysfs: Remove support for tagged directories with untagged members (again)

2011-10-25T13:10:28Z

In commit 8a9ea3237e7e ("Merge git://.../davem/net-next") where my sysfs changes from the net tree merged with the sysfs rbtree changes from Mickulas Patocka the conflict resolution failed to preserve the simplified property that was the point of my changes. That is sysfs_find_dirent can now say something is a match if and only s_name and s_ns match what we are looking for, and sysfs_readdir can simply return all of the directory entries where s_ns matches the directory that we should be returning. Now that we are back to exact matches we can tweak sysfs_find_dirent and the name rb_tree to order sysfs_dirents by s_ns s_name and remove the second loop in sysfs_find_dirent. However that change seems a bit much for a conflict resolution so it can come later. Signed-off-by: Eric W. Biederman Signed-off-by: Linus Torvalds