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2007-07-11sysfs: implement sysfs_get_dentry()Tejun Heo
Some sysfs operations require dentry and inode. sysfs_get_dentry() looks up and gets dentry for the specified sysfs_dirent. It finds the first ancestor with dentry attached and starts looking up dentries from there. Looking up from the nearest ancestor is necessary to support shadowed directories because we can't reliably lookup dentry for one of the shadows. Dentries for each shadow will be pinned in memory such that they can serve as the starting point for dentry lookup. Signed-off-by: Tejun Heo <htejun@gmail.com> 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_find_dirent() and sysfs_get_dirent()Tejun Heo
Implement sysfs_find_dirent() and sysfs_get_dirent(). sysfs_dirent_exist() is replaced by sysfs_find_dirent(). These 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: 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: slim down sysfs_dirent->s_activeTejun Heo
Make sysfs_dirent->s_active an atomic_t instead of rwsem. This reduces the size of sysfs_dirent from 136 to 104 on 64bit and from 76 to 60 on 32bit with lock debugging turned off. With lock debugging turned on the reduction is much larger. s_active starts at zero and each active reference increments s_active. Putting a reference decrements s_active. Deactivation subtracts SD_DEACTIVATED_BIAS which is currently INT_MIN and assumed to be small enough to make s_active negative. If s_active is negative, sysfs_get() no longer grants new references. Deactivation succeeds immediately if there is no active user; otherwise, it waits using a completion for the last put. Due to the removal of lockdep tricks, this change makes things less trickier in release_sysfs_dirent(). As all the complexity is contained in three s_active functions, I think it's more readable this way. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: move s_active functions to fs/sysfs/dir.cTejun Heo
These functions are about to receive more complexity and doesn't really need to be inlined in the first place. Move them from fs/sysfs/sysfs.h to fs/sysfs/dir.c. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: fix root sysfs_dirent -> root dentry associationTejun Heo
The root sysfs_dirent didn't point to the root dentry fix it. 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: fix parent refcounting during rename and moveTejun Heo
Parent reference wasn't properly transferred during rename and move. Fix it. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: make sysfs_alloc_ino() staticTejun Heo
sysfs_alloc_ino() isn't used out side of fs/sysfs/dir.c. Make it static. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: kill unnecessary attribute->ownerTejun Heo
sysfs is now completely out of driver/module lifetime game. After deletion, a sysfs node doesn't access anything outside sysfs proper, so there's no reason to hold onto the attribute owners. Note that often the wrong modules were accounted for as owners leading to accessing removed modules. This patch kills now unnecessary attribute->owner. Note that with this change, userland holding a sysfs node does not prevent the backing module from being unloaded. For more info regarding lifetime rule cleanup, please read the following message. http://article.gmane.org/gmane.linux.kernel/510293 (tweaked by Greg to not delete the field just yet, to make it easier to merge things properly.) Signed-off-by: Tejun Heo <htejun@gmail.com> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> 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: implement bin_bufferTejun Heo
Implement bin_buffer which contains a mutex and pointer to PAGE_SIZE buffer to properly synchronize accesses to per-openfile buffer and prepare for immediate-kobj-disconnect. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: reimplement symlink using sysfs_dirent treeTejun Heo
sysfs symlink is implemented by referencing dentry and kobject from sysfs_dirent - symlink entry references kobject, dentry is used to walk the tree. This complicates object lifetimes rules and is dangerous - for example, there is no way to tell to which module the target of a symlink belongs and referencing that kobject can make it linger after the module is gone. This patch reimplements symlink using only sysfs_dirent tree. sd for a symlink points and holds reference to the target sysfs_dirent and all walking is done using sysfs_dirent tree. Simpler and safer. 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: implement kobj_sysfs_assoc_lockTejun Heo
kobj->dentry can go away anytime unless the user controls when the associated sysfs node is deleted. This patch implements kobj_sysfs_assoc_lock which protects kobj->dentry. This will be used to maintain kobj based API when converting sysfs to use sysfs_dirent tree instead of dentry/kobject. Note that this lock belongs to kobject/driver-model not sysfs. Once sysfs is converted to not use kobject in its interface, this can be removed from sysfs. 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: 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>
2007-07-11sysfs: add sysfs_dirent->s_parentTejun Heo
Add sysfs_dirent->s_parent. With this patch, each sd points to and holds a reference to its parent. This allows walking sysfs tree without referencing sd->s_dentry which can go away anytime if the user doesn't control when it's deleted. sd->s_parent is initialized and parent is referenced in sysfs_attach_dirent(). Reference to parent is released when the sd is released, so as long as reference to a sd is held, s_parent can be followed. dentry walk in sysfs_readdir() is convereted to s_parent walk. This will be used to reimplement symlink such that it uses only sysfs_dirent tree. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: consolidate sysfs_dirent creation functionsTejun Heo
Currently there are four functions to create sysfs_dirent - __sysfs_new_dirent(), sysfs_new_dirent(), __sysfs_make_dirent() and sysfs_make_dirent(). Other than sysfs_make_dirent(), no function has two users if calls to implement other functions are excluded. This patch consolidates sysfs_dirent creation functions into the following two. * sysfs_new_dirent() : allocate and initialize * sysfs_attach_dirent() : attach to sysfs_dirent hierarchy and/or associate with dentry This simplifies interface and gives callers more flexibility. 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: flatten and fix sysfs_rename_dir() error handlingTejun Heo
Error handling in sysfs_rename_dir() was broken. * When lookup_one_len() fails, 0 is returned. * If parent inode check fails, returns with inode mutex and rename rwsem held. This patch fixes the above bugs and flattens error handling such that it's more readable and easier to modify. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: flatten cleanup paths in sysfs_add_link() and create_dir()Tejun Heo
Flatten cleanup paths in sysfs_add_link() and create_dir() to improve readability and ease further changes to these functions. 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: fix error handling in binattr write()Tejun Heo
Error handling in fs/sysfs/bin.c:write() was wrong because size_t count is used to receive return value from flush_write() which is negative on failure. This patch updates write() such that int variable is used instead. read() is updated the same way for consistency. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: make sysfs_put() ignore NULL sdTejun Heo
Make sysfs_put() ignore NULL sd instead of oopsing. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: allocate inode number using idaTejun Heo
sysfs used simple incrementing allocator which is not guaranteed to be unique. This patch makes sysfs use ida to give each sd a unique and packed inode number. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: move release_sysfs_dirent() to dir.cTejun Heo
There is no reason this function should be inlined and soon to follow sysfs object reference simplification will make it heavier. Move it to dir.c. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11debugfs: add rename for debugfs filesJan Kara
Implement debugfs_rename() to allow renaming files/directories in debugfs. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-10NFSv4: Make sure unlock is really an unlock when cancelling a lockFrank Filz
I ran into a curious issue when a lock is being canceled. The cancellation results in a lock request to the vfs layer instead of an unlock request. This is particularly insidious when the process that owns the lock is exiting. In that case, sometimes the erroneous lock is applied AFTER the process has entered zombie state, preventing the lock from ever being released. Eventually other processes block on the lock causing a slow degredation of the system. In the 2.6.16 kernel this was investigated on, the problem is compounded by the fact that the cl_sem is held while blocking on the vfs lock, which results in most processes accessing the nfs file system in question hanging. In more detail, here is how the situation occurs: first _nfs4_do_setlk(): static int _nfs4_do_setlk(struct nfs4_state *state, int cmd, struct file_lock *fl, int reclaim) ... ret = nfs4_wait_for_completion_rpc_task(task); if (ret == 0) { ... } else data->cancelled = 1; then nfs4_lock_release(): static void nfs4_lock_release(void *calldata) ... if (data->cancelled != 0) { struct rpc_task *task; task = nfs4_do_unlck(&data->fl, data->ctx, data->lsp, data->arg.lock_seqid); The problem is the same file_lock that was passed in to _nfs4_do_setlk() gets passed to nfs4_do_unlck() from nfs4_lock_release(). So the type is still F_RDLCK or FWRLCK, not F_UNLCK. At some point, when cancelling the lock, the type needs to be changed to F_UNLCK. It seemed easiest to do that in nfs4_do_unlck(), but it could be done in nfs4_lock_release(). The concern I had with doing it there was if something still needed the original file_lock, though it turns out the original file_lock still needs to be modified by nfs4_do_unlck() because nfs4_do_unlck() uses the original file_lock to pass to the vfs layer, and a copy of the original file_lock for the RPC request. It seems like the simplest solution is to force all situations where nfs4_do_unlck() is being used to result in an unlock, so with that in mind, I made the following change: Signed-off-by: Frank Filz <ffilzlnx@us.ibm.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10NLM: fix source address of callback to clientFrank van Maarseveen
Use the destination address of the original NLM request as the source address in callbacks to the client. Signed-off-by: Frank van Maarseveen <frankvm@frankvm.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10NFSv4: Make the NFS state model work with the nosharedcache mount optionTrond Myklebust
Consider the case where the user has mounted the remote filesystem server:/foo on the two local directories /bar and /baz using the nosharedcache mount option. The files /bar/file and /baz/file are represented by different inodes in the local namespace, but refer to the same file /foo/file on the server. Consider the case where a process opens both /bar/file and /baz/file, then closes /bar/file: because the nfs4_state is not shared between /bar/file and /baz/file, the kernel will see that the nfs4_state for /bar/file is no longer referenced, so it will send off a CLOSE rpc call. Unless the open_owners differ, then that CLOSE call will invalidate the open state on /baz/file too. Conclusion: we cannot share open state owners between two different non-shared mount instances of the same filesystem. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10NFS: Error when mounting the same filesystem with different optionsTrond Myklebust
Unless the user sets the NFS_MOUNT_NOSHAREDCACHE mount flag, we should return EBUSY if the filesystem is already mounted on a superblock that has set conflicting mount options. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10NFS: Add the mount option "nosharecache"Trond Myklebust
Prior to David Howell's mount changes in 2.6.18, users who mounted different directories which happened to be from the same filesystem on the server would get different super blocks, and hence could choose different mount options. As long as there were no hard linked files that crossed from one subtree to another, this was quite safe. Post the changes, if the two directories are on the same filesystem (have the same 'fsid'), they will share the same super block, and hence the same mount options. Add a flag to allow users to elect not to share the NFS super block with another mount point, even if the fsids are the same. This will allow users to set different mount options for the two different super blocks, as was previously possible. It is still up to the user to ensure that there are no cache coherency issues when doing this, however the default behaviour will be to share super blocks whenever two paths result in the same fsid. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10NFS: Add support for mounting NFSv4 file systems with string optionsChuck Lever
Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10NFS: Add final pieces to support in-kernel mount option parsingChuck Lever
Hook in final components required for supporting in-kernel mount option parsing for NFSv2 and NFSv3 mounts. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10NFS: Introduce generic mount client APIChuck Lever
For NFSv2 and v3 mounts, the first step is to contact the server's MOUNTD and request the file handle for the root of the mounted share. Add a function to the NFS client that handles this operation. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10NFS: Add enums and match tables for mount option parsingChuck Lever
This generic infrastructure works for both NFS and NFSv4 mounts. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10NFS: Improve debugging output in NFS in-kernel mount clientChuck Lever
Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10NFS: Clean up in-kernel NFS mountChuck Lever
Clean up white space and coding conventions. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10NFS: Remake nfsroot_mount as a permanent part of NFS clientChuck Lever
In preparation for supporting NFSv2 and NFSv3 mount option handling in the kernel NFS client, convert mount_clnt.c to be a permanent part of the NFS client, instead of built only when CONFIG_ROOT_NFS is enabled. In addition, we also replace the "struct sockaddr_in *" argument with something more generic, to help support IPv6 at some later point. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>