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path: root/fs/sysfs/inode.c
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2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-07sysfs: Pass super_block to sysfs_get_inodeEric W. Biederman
Currently sysfs_get_inode magically returns an inode on sysfs_sb. Make the super_block parameter explicit and the code becomes clearer. Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-03-07sysfs: Serialize updates to the vfs inodeEric W. Biederman
The vfs depends upon filesystem methods to update the vfs inode. Sysfs adds to the normal number of places where the vfs inode is updated by also updatng the vfs inode in sysfs_refresh_inode. Typically the inode mutex is used to serialize updates to the vfs inode, but grabbing the inode mutex in sysfs_permission and sysfs_getattr causes deadlocks, because sometimes the vfs calls those operations with the inode mutex held. Therefore sysfs can not use the inode mutex to serial updates to the vfs inode. The sysfs_mutex is acquired in all of the routines where sysfs updates the vfs inode, and with a small change we can consistently protext sysfs vfs inode updates with the sysfs_mutex. To protect the sysfs vfs inode updates with the sysfs_mutex simply requires extending the scope of sysfs_mutex in sysfs_setattr over inode_setattr, and over inode_change_ok (so we have an unchanging inode when we perform the check). Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-02-16sysfs: sysfs_sd_setattr set iattrs unconditionallyEric W. Biederman
There is currently a bug in sysfs_sd_setattr inherited from sysfs_setattr in 2.6.32 where the first time we set the attributes on a sysfs file we allocate backing store but do not set the backing store attributes. Resulting in overly restrictive permissions on sysfs files. The fix is to simply modify the code so that it always executes when we update the sysfs attributes, as we did in 2.6.31 and earlier. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Tested-by: Jean Delvare <khali@linux-fr.org> Cc: stable <stable@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-12-11sysfs: sysfs_setattr remove unnecessary permission check.Eric W. Biederman
inode_change_ok already clears the SGID bit when necessary so there is no reason for sysfs_setattr to carry code to do the same, and it is good to kill the extra copy because when I moved the code last in certain corner cases the code will look at the wrong gid. Acked-by: Serge Hallyn <serue@us.ibm.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-12-11sysfs: Propagate renames to the vfs on demandEric W. Biederman
By teaching sysfs_revalidate to hide a dentry for a sysfs_dirent if the sysfs_dirent has been renamed, and by teaching sysfs_lookup to return the original dentry if the sysfs dirent has been renamed. I can show the results of renames correctly without having to update the dcache during the directory rename. This massively simplifies the rename logic allowing a lot of weird sysfs special cases to be removed along with a lot of now unnecesary helper code. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-12-11sysfs: Implement sysfs_getattr & sysfs_permissionEric W. Biederman
With the implementation of sysfs_getattr and sysfs_permission sysfs becomes able to lazily propogate inode attribute changes from the sysfs_dirents to the vfs inodes. This paves the way for deleting significant chunks of now unnecessary code. While doing this we did not reference sysfs_setattr from sysfs_symlink_inode_operations so I added along with sysfs_getattr and sysfs_permission. Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-12-11sysfs: Fix locking and factor out sysfs_sd_setattrEric W. Biederman
Cleanly separate the work that is specific to setting the attributes of a sysfs_dirent from what is needed to update the attributes of a vfs inode. Additionally grab the sysfs_mutex to keep any nasties from surprising us when updating the sysfs_dirent. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-12-11sysfs: Simplify iattr time assignmentsEric W. Biederman
The granularity of sysfs time when we keep it is 1 ns. Which when passed to timestamp_trunc results in a nop. So remove the unnecessary function call making sysfs_setattr slightly easier to read. Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-12-11sysfs: Update sysfs_setxattr so it updates secdata under the sysfs_mutexEric W. Biederman
The sysfs_mutex is required to ensure updates are and will remain atomic with respect to other inode iattr updates, that do not happen through the filesystem. Acked-by: Serge Hallyn <serue@us.ibm.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-12-11sysfs: mark a locally-only used function staticStefan Richter
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> Acked-by: David P. Quigley <dpquigl@tycho.nsa.gov> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-09-11Merge branch 'writeback' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds
* 'writeback' of git://git.kernel.dk/linux-2.6-block: writeback: check for registered bdi in flusher add and inode dirty writeback: add name to backing_dev_info writeback: add some debug inode list counters to bdi stats writeback: get rid of pdflush completely writeback: switch to per-bdi threads for flushing data writeback: move dirty inodes from super_block to backing_dev_info writeback: get rid of generic_sync_sb_inodes() export
2009-09-11writeback: add name to backing_dev_infoJens Axboe
This enables us to track who does what and print info. Its main use is catching dirty inodes on the default_backing_dev_info, so we can fix that up. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-10sysfs: Add labeling support for sysfsDavid P. Quigley
This patch adds a setxattr handler to the file, directory, and symlink inode_operations structures for sysfs. The patch uses hooks introduced in the previous patch to handle the getting and setting of security information for the sysfs inodes. As was suggested by Eric Biederman the struct iattr in the sysfs_dirent structure has been replaced by a structure which contains the iattr, secdata and secdata length to allow the changes to persist in the event that the inode representing the sysfs_dirent is evicted. Because sysfs only stores this information when a change is made all the optional data is moved into one dynamically allocated field. This patch addresses an issue where SELinux was denying virtd access to the PCI configuration entries in sysfs. The lack of setxattr handlers for sysfs required that a single label be assigned to all entries in sysfs. Granting virtd access to every entry in sysfs is not an acceptable solution so fine grained labeling of sysfs is required such that individual entries can be labeled appropriately. [sds: Fixed compile-time warnings, coding style, and setting of inode security init flags.] Signed-off-by: David P. Quigley <dpquigl@tycho.nsa.gov> Signed-off-by: Stephen D. Smalley <sds@tycho.nsa.gov> Signed-off-by: James Morris <jmorris@namei.org>
2009-03-24sysfs: reference sysfs_dirent from sysfs inodesEric W. Biederman
The sysfs_dirent serves as both an inode and a directory entry for sysfs. To prevent the sysfs inode numbers from being freed prematurely hold a reference to sysfs_dirent from the sysfs inode. [akpm@linux-foundation.org: add comment] Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com> Cc: Tejun Heo <tj@kernel.org> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-01-05zero i_uid/i_gid on inode allocationAl Viro
... and don't bother in callers. Don't bother with zeroing i_blocks, while we are at it - it's already been zeroed. i_mode is not worth the effort; it has no common default value. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-30sysfs: Disallow truncation of files in sysfsBen Hutchings
sysfs allows attribute files to be truncated, e.g. using ftruncate(), with the expected effect on their inode. For most attributes, this doesn't change the "real" size of the file i.e. how much can be read from it. However, the parameter validation for reading and writing binary attribute files is based on the inode size and not the size specified in the file's bin_attribute, so it can be broken by this. For example, if we try using dd to write to such a file: # pwd /sys/bus/pci/devices/0000:08:00.0 # ls -l config -rw-r--r-- 1 root root 4096 Feb 1 17:35 config # dd if=/dev/zero of=config bs=4 count=1 1+0 records in 1+0 records out # ls -l config -rw-r--r-- 1 root root 0 Feb 1 17:50 config # dd if=/dev/zero of=config bs=4 count=1 seek=128 dd: writing `config': No space left on device 1+0 records in 0+0 records out Also, after truncation to 0, parameter validation for read and write is disabled. Most bin_attribute read and write methods also validate the size and offset, but for some this will allow out-of-range access. This may be a security issue, though access to such files is often limited to root. In any case, the validation should remain for safety's sake!) This was previously reported in Bugzilla as bug 9867. sysfs should ignore size changes or else refuse them (by returning -EINVAL). This patch makes it ignore them. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-04-30mm: bdi: add separate writeback accounting capabilityMiklos Szeredi
Add a new BDI capability flag: BDI_CAP_NO_ACCT_WB. If this flag is set, then don't update the per-bdi writeback stats from test_set_page_writeback() and test_clear_page_writeback(). Misc cleanups: - convert bdi_cap_writeback_dirty() and friends to static inline functions - create a flag that includes all three dirty/writeback related flags, since almst all users will want to have them toghether Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17mm: bdi init hooksPeter Zijlstra
provide BDI constructor/destructor hooks [akpm@linux-foundation.org: compile fix] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16implement simple fs aopsNick Piggin
Implement new aops for some of the simpler filesystems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-12sysfs: add copyrightsTejun Heo
Sysfs has gone through considerable amount of reimplementation. Add copyrights. Any objections? :-) Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12sysfs: move sysfs_dirent->s_children into sysfs_dirent->s_dirTejun Heo
Children list head is only meaninful for directory nodes. Move it into s_dir. This doesn't save any space currently but it will with further changes. Signed-off-by: Tejun Heo <htejun@gmail.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12sysfs: make sysfs_root a regular directory direntTejun Heo
sysfs_root is different from a regular directory dirent in that it's of type SYSFS_ROOT and doesn't have a name. These differences aren't used by anybody and only adds to complexity. Make sysfs_root a regular directory dirent. Signed-off-by: Tejun Heo <htejun@gmail.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12sysfs: make s_elem an anonymous unionTejun Heo
Make s_elem an anonymous union. Prefixing with s_elem makes things needlessly longer without any advantage. Signed-off-by: Tejun Heo <htejun@gmail.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12sysfs: Remove sysfs_instantiateEric W. Biederman
Now that sysfs_get_inode is dropping the inode lock we no longer have a need from sysfs_instantiate. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Tejun Heo <htejun@gmail.com> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12sysfs: Move all of inode initialization into sysfs_init_inodeEric W. Biederman
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Tejun Heo <htejun@gmail.com> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12sysfs: make sysfs_addrm_finish() return voidTejun Heo
With the previous sysfs_add_one() update, there is only one user of the return value of sysfs_addrm_finish() and the user can switch to testing @sd easily. Make sysfs_addrm_finish() return void for cleaner semantics as suggested by Satyam Sharma. This patch doesn't introduce any noticeable behavior change. Signed-off-by: Tejun Heo <htejun@gmail.com> Cc: Satyam Sharma <satyam.sharma@gmail.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12sysfs: make sysfs_add/remove_one() call link/unlink_sibling() implictlyTejun Heo
When adding or removing a sysfs_dirent, the user used to be required to call link/unlink separately. It was for two reasons - code looked like that before sysfs_addrm_cxt conversion and to avoid looping through parent_sd->children list twice during removal. Performance optimization during removal just isn't worth it. Make sysfs_add/remove_one() call sysfs_link/unlink_sibing() implicitly. This makes code simpler albeit slightly less efficient. This change doesn't introduce any noticeable behavior change. Signed-off-by: Tejun Heo <htejun@gmail.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12sysfs: Remove first pass at shadow directory supportEric W. Biederman
While shadow directories appear to be a good idea, the current scheme of controlling their creation and destruction outside of sysfs appears to be a locking and maintenance nightmare in the face of sysfs directories dynamically coming and going. Which can now occur for directories containing network devices when CONFIG_SYSFS_DEPRECATED is not set. This patch removes everything from the initial shadow directory support that allowed the shadow directory creation to be controlled at a higher level. So except for a few bits of sysfs_rename_dir everything from commit b592fcfe7f06c15ec11774b5be7ce0de3aa86e73 is now gone. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12sysfs: cleanup semaphore.hDave Young
Cleanup semaphore.h Signed-off-by: Dave Young <hidave.darkstar@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-18sysfs: make sysfs_init_inode() staticTejun Heo
With sysfs_fill_super() converted to use sysfs_get_inode(), there is no user of sysfs_init_inode() outside of fs/sysfs/inode.c. Make it static. Signed-off-by: Tejun Heo <htejun@gmail.com> Acked-by: Jean Delvare <khali@linux-fr.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: move sysfs_drop_dentry() to dir.c and make it staticTejun Heo
After add/remove path restructuring, the only user of sysfs_drop_dentry() is sysfs_addrm_finish(). Move sysfs_drop_dentry() to dir.c and make it static. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: restructure add/remove paths and fix inode updateTejun Heo
The original add/remove code had the following problems. * parent's timestamps are updated on dentry instantiation. this is incorrect with reclaimable files. * updating parent's timestamps isn't synchronized. * parent nlink update assumes the inode is accessible which won't be true once directory dentries are made reclaimable. This patch restructures add/remove paths to resolve the above problems. Add/removal are done in the following steps. 1. sysfs_addrm_start() : acquire locks including sysfs_mutex and other resources. 2-a. sysfs_add_one() : add new sd. linking the new sd into the children list is caller's responsibility. 2-b. sysfs_remove_one() : remove a sd. unlinking the sd from the children list is caller's responsibility. 3. sysfs_addrm_finish() : release all resources and clean up. Steps 2-a and/or 2-b can be repeated multiple times. Parent's inode is looked up during sysfs_addrm_start(). If available (always at the moment), it's pinned and nlink is updated as sd's are added and removed. Timestamps are updated during finish if any sd has been added or removed. If parent's inode is not available during start, sysfs_mutex ensures that parent inode is not created till add/remove is complete. All the complexity is contained inside the helper functions. Especially, dentry/inode handling is properly hidden from the rest of sysfs which now mostly operate on sysfs_dirents. As an added bonus, codes which use these helpers to add and remove sysfs_dirents are now more structured and simpler. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: use sysfs_mutex to protect the sysfs_dirent treeTejun Heo
As kobj sysfs dentries and inodes are gonna be made reclaimable, i_mutex can't be used to protect sysfs_dirent tree. Use sysfs_mutex globally instead. As the whole tree is protected with sysfs_mutex, there is no reason to keep sysfs_rename_sem. Drop it. While at it, add docbook comments to functions which require sysfs_mutex locking. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: consolidate sysfs spinlocksTejun Heo
Replace sysfs_lock and kobj_sysfs_assoc_lock with sysfs_assoc_lock. sysfs_lock was originally to be used to protect sysfs_dirent tree but mutex seems better choice, so there is no reason to keep sysfs_lock separate. Merge the two spinlocks into one. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: make kobj point to sysfs_dirent instead of dentryTejun Heo
As kobj sysfs dentries and inodes are gonna be made reclaimable, dentry can't be used as naming token for sysfs file/directory, replace kobj->dentry with kobj->sd. The only external interface change is shadow directory handling. All other changes are contained in kobj and sysfs. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: implement SYSFS_FLAG_REMOVED flagTejun Heo
Implement SYSFS_FLAG_REMOVED flag which currently is used only to improve sanity check in sysfs_deactivate(). The flag will be used to make directory entries reclamiable. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: rename sysfs_dirent->s_type to s_flags and make room for flagsTejun Heo
Rename sysfs_dirent->s_type to s_flags, pack type into lower eight bits and reserve the rest for flags. sysfs_type() can used to access the type. All existing sd->s_type accesses are converted to use sysfs_type(). While at it, type test is changed to equality test instead of bit-and test where appropriate. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: make sysfs_drop_dentry() access inodes using ilookup()Tejun Heo
sysfs_drop_dentry() used to go through sd->s_dentry and sd->s_parent->s_dentry to access the inodes. This is incorrect because inode can be cached without dentry. This patch makes sysfs_drop_dentry() access inodes using ilookup() on sd->s_ino. This is both correct and simpler. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: Fix oops in sysfs_drop_dentry on x86_64Rafael J. Wysocki
Fix oops on x86_64 caused by the dereference of dir in sysfs_drop_dentry() made before checking if dir is not NULL (cf. http://marc.info/?l=linux-kernel&m=118151626704924&w=2). Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: use singly-linked list for sysfs_dirent treeTejun Heo
Make sysfs_dirent use singly linked list for its tree structure. sysfs_link_sibling() and sysfs_unlink_sibling() functions are added to handle simpler cases. It adds some complexity and cpu cycle overhead but reduced memory footprint is worthwhile on big machines. This change reduces the sizeof sysfs_dirent from 104 to 88 on 64bit and from 60 to 52 on 32bit. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: use iget_locked() instead of new_inode()Tejun Heo
After dentry is reclaimed, sysfs always used to allocate new dentry and inode if the file is accessed again. This causes problem with operations which only pin the inode. For example, if inotify watch is added to a sysfs file and the dentry for the file is reclaimed, the next update event creates new dentry and new inode making the inotify watch miss all the events from there on. This patch fixes it by using iget_locked() instead of new_inode(). sysfs_new_inode() is renamed to sysfs_get_inode() and inode is initialized iff the inode is newly allocated. sysfs_instantiate() is responsible for unlocking new inodes. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: reorganize sysfs_new_indoe() and sysfs_create()Tejun Heo
Reorganize/clean up sysfs_new_inode() and sysfs_create(). * sysfs_init_inode() is separated out from sysfs_new_inode() and is responsible for basic initialization. * sysfs_instantiate() replaces the last step of sysfs_create() and is responsible for dentry instantitaion. * type-specific initialization is moved out to the callers. * mode is specified only once when creating a sysfs_dirent. * spurious list_del_init(&sd->s_sibling) dropped from create_dir() This change is to * prepare for inode allocation fix. * separate alloc and init code for synchronization update. * make dentry/inode initialization more flexible for later changes. This patch doesn't introduce visible behavior change. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: reimplement sysfs_drop_dentry()Tejun Heo
This patch reimplements sysfs_drop_dentry() such that remove_dir() can use it to drop dentry instead of using a separate mechanism. With this change, making directories reclaimable is much easier. This patch used to contain fixes for two race conditions around sd->s_dentry but that part has been separated out and included into mainline early as commit 6aa054aadfea613a437ad0b15d38eca2b963fc0a and dd14cbc994709a1c5a64ed3621f583c49a27e521. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: separate out sysfs_attach_dentry()Tejun Heo
Consolidate sd <-> dentry association into sysfs_attach_dentry() and call it after dentry and inode are properly set up. This is in preparation of sysfs_drop_dentry() updates. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: kill attribute file orphaningTejun Heo
Now that sysfs_dirent can be disconnected from kobject on deletion, there is no need to orphan each attribute files. All [bin_]attribute nodes are automatically orphaned when the parent node is deleted. Kill attribute file orphaning. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: implement sysfs_dirent active reference and immediate disconnectTejun Heo
sysfs: implement sysfs_dirent active reference and immediate disconnect Opening a sysfs node references its associated kobject, so userland can arbitrarily prolong lifetime of a kobject which complicates lifetime rules in drivers. This patch implements active reference and makes the association between kobject and sysfs immediately breakable. Now each sysfs_dirent has two reference counts - s_count and s_active. s_count is a regular reference count which guarantees that the containing sysfs_dirent is accessible. As long as s_count reference is held, all sysfs internal fields in sysfs_dirent are accessible including s_parent and s_name. The newly added s_active is active reference count. This is acquired by invoking sysfs_get_active() and it's the caller's responsibility to ensure sysfs_dirent itself is accessible (should be holding s_count one way or the other). Dereferencing sysfs_dirent to access objects out of sysfs proper requires active reference. This includes access to the associated kobjects, attributes and ops. The active references can be drained and denied by calling sysfs_deactivate(). All active sysfs_dirents must be deactivated after deletion but before the default reference is dropped. This enables immediate disconnect of sysfs nodes. Once a sysfs_dirent is deleted, it won't access any entity external to sysfs proper. Because attr/bin_attr ops access both the node itself and its parent for kobject, they need to hold active references to both. sysfs_get/put_active_two() helpers are provided to help grabbing both references. Parent's is acquired first and released last. Unlike other operations, mmapped area lingers on after mmap() is finished and the module implement implementing it and kobj need to stay referenced till all the mapped pages are gone. This is accomplished by holding one set of active references to the bin_attr and its parent if there have been any mmap during lifetime of an openfile. The references are dropped when the openfile is released. This change makes sysfs lifetime rules independent from both kobject's and module's. It not only fixes several race conditions caused by sysfs not holding onto the proper module when referencing kobject, but also helps fixing and simplifying lifetime management in driver model and drivers by taking sysfs out of the equation. Please read the following message for more info. http://article.gmane.org/gmane.linux.kernel/510293 Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: make sysfs_dirent->s_element a unionTejun Heo
Make sd->s_element a union of sysfs_elem_{dir|symlink|attr|bin_attr} and rename it to s_elem. This is to achieve... * some level of type checking : changing symlink to point to sysfs_dirent instead of kobject is much safer and less painful now. * easier / standardized dereferencing * allow sysfs_elem_* to contain more than one entry Where possible, pointer is obtained by directly deferencing from sd instead of going through other entities. This reduces dependencies to dentry, inode and kobject. to_attr() and to_bin_attr() are unused now and removed. This is in preparation of object reference simplification. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: add sysfs_dirent->s_nameTejun Heo
Add s_name to sysfs_dirent. This is to further reduce dependency to the associated dentry. Name is copied for directories and symlinks but not for attributes. Where possible, name dereferences are converted to use sd->s_name. sysfs_symlink->link_name and sysfs_get_name() are unused now and removed. This change allows symlink to be implemented using sysfs_dirent tree proper, which is the last remaining dentry-dependent sysfs walk. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-06-12sysfs: fix race condition around sd->s_dentry, take#2Tejun Heo
Allowing attribute and symlink dentries to be reclaimed means sd->s_dentry can change dynamically. However, updates to the field are unsynchronized leading to race conditions. This patch adds sysfs_lock and use it to synchronize updates to sd->s_dentry. Due to the locking around ->d_iput, the check in sysfs_drop_dentry() is complex. sysfs_lock only protect sd->s_dentry pointer itself. The validity of the dentry is protected by dcache_lock, so whether dentry is alive or not can only be tested while holding both locks. This is minimal backport of sysfs_drop_dentry() rewrite in devel branch. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>