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path: root/fs/nfs/inode.c
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2007-10-09NFS: Don't revalidate dentries on directory size or ctime changesTrond Myklebust
We only need to look at the mtime changes... Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-09NFS: Don't set cache_change_attribute in nfs_revalidate_mappingTrond Myklebust
The attribute revalidation code will already have taken care of resetting nfsi->cache_change_attribute. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-09NFS: Fake up 'wcc' attributes to prevent cache invalidation after writeTrond Myklebust
NFSv2 and v4 don't offer weak cache consistency attributes on WRITE calls. In NFSv3, returning wcc data is optional. In all cases, we want to prevent the client from invalidating our cached data whenever ->write_done() attempts to update the inode attributes. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-09NFS: Remove bogus check of cache_change_attribute in nfs_update_inodeTrond Myklebust
Remove the bogus 'data_stable' check in nfs_update_inode. The cache_change_attribute tells you if the directory changed on the server, and should have nothing to do with the file length. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-09NFS: Fix the ESTALE "revalidation" in _nfs_revalidate_inode()Trond Myklebust
For one thing, the test NFS_ATTRTIMEO() == 0 makes no sense: we're testing whether or not the cache timeout length is zero, which is totally unrelated to the issue of whether or not we trust the file staleness. Secondly, we do not want to retry the GETATTR once a file has been declared stale by the server: we rather want to discard that inode as soon as possible, since there are broken servers still in use out there that reuse filehandles on new files. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-09NFS: Fix atime revalidation in readdir()Trond Myklebust
NFSv3 will correctly update atime on a readdir call, so there is no need to set the NFS_INO_INVALID_ATIME flag unless the call to nfs_refresh_inode() fails. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-09NFSv4: Don't use ctime/mtime for determining when to invalidate the cachesTrond Myklebust
In NFSv4 we should only be looking at the change attribute. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-09NFS: Don't force a dcache revalidation if nfs_wcc_update_inode succeedsTrond Myklebust
The reason is that if the weak cache consistency update was successful, then we know that our client must be the only one that changed the directory, and we've already updated the dcache to reflect the change. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-09NFS: nfs_wcc_update_inode: directory caches are always invalidatedTrond Myklebust
We must ensure that the readdir data is always invalidated whether or not the weak cache consistency data update succeeds. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-09NFS: Fix dcache revalidation bugsTrond Myklebust
We don't need to force a dentry lookup just because we're making changes to the directory. Don't update nfsi->cache_change_attribute in nfs_end_data_update: that overrides the NFSv3/v4 weak consistency checking that tells us our update was the only one, and that tells us the dcache is still valid. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-09NFS: fix nfs_verify_change_attributeTrond Myklebust
We always want to check that the verifier and directory cache_change_attribute match. This also allows us to remove the 'wraparound hack' for the cache_change_attribute. If we're only checking for equality, then we don't care about wraparound issues. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-09NFS: nfs_post_op_update_inode() should call nfs_refresh_inode()Trond Myklebust
Ensure that we don't clobber the results from a more recent getattr call... Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-09NFS: Fix over-conservative attribute invalidation in nfs_update_inode()Trond Myklebust
We should always be declaring the attribute cache as valid after having updated it. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-09NFS: Replace file->private_data with calls to nfs_file_open_context()Trond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-09Re: [NFS] [PATCH] Attribute timeout handling and wrapping u32 jiffiesFabio Olive Leite
I would like to discuss the idea that the current checks for attribute timeout using time_after are inadequate for 32bit architectures, since time_after works correctly only when the two timestamps being compared are within 2^31 jiffies of each other. The signed overflow caused by comparing values more than 2^31 jiffies apart will flip the result, causing incorrect assumptions of validity. 2^31 jiffies is a fairly large period of time (~25 days) when compared to the lifetime of most kernel data structures, but for long lived NFS mounts that can sit idle for months (think that for some reason autofs cannot be used), it is easy to compare inode attribute timestamps with very disparate or even bogus values (as in when jiffies have wrapped many times, where the comparison doesn't even make sense). Currently the code tests for attribute timeout by simply adding the desired amount of jiffies to the stored timestamp and comparing that with the current timestamp of obtained attribute data with time_after. This is incorrect, as it returns true for the desired timeout period and another full 2^31 range of jiffies. In testing with artificial jumps (several small jumps, not one big crank) of the jiffies I was able to reproduce a problem found in a server with very long lived NFS mounts, where attributes would not be refreshed even after touching files and directories in the server: Initial uptime: 03:42:01 up 6 min, 0 users, load average: 0.01, 0.12, 0.07 NFS volume is mounted and time is advanced: 03:38:09 up 25 days, 2 min, 0 users, load average: 1.22, 1.05, 1.08 # ls -l /local/A/foo/bar /nfs/A/foo/bar -rw-r--r-- 1 root root 0 Dec 17 03:38 /local/A/foo/bar -rw-r--r-- 1 root root 0 Nov 22 00:36 /nfs/A/foo/bar # touch /local/A/foo/bar # ls -l /local/A/foo/bar /nfs/A/foo/bar -rw-r--r-- 1 root root 0 Dec 17 03:47 /local/A/foo/bar -rw-r--r-- 1 root root 0 Nov 22 00:36 /nfs/A/foo/bar We can see the local mtime is updated, but the NFS mount still shows the old value. The patch below makes it work: Initial setup... 07:11:02 up 25 days, 1 min, 0 users, load average: 0.15, 0.03, 0.04 # ls -l /local/A/foo/bar /nfs/A/foo/bar -rw-r--r-- 1 root root 0 Jan 11 07:11 /local/A/foo/bar -rw-r--r-- 1 root root 0 Jan 11 07:11 /nfs/A/foo/bar # touch /local/A/foo/bar # ls -l /local/A/foo/bar /nfs/A/foo/bar -rw-r--r-- 1 root root 0 Jan 11 07:14 /local/A/foo/bar -rw-r--r-- 1 root root 0 Jan 11 07:14 /nfs/A/foo/bar Signed-off-by: Fabio Olive Leite <fleite@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-0964 bit ino support for NFS clientPeter Staubach
Hi. Attached is a patch to modify the NFS client code to support 64 bit ino's, as appropriate for the system and the NFS protocol version. The code basically just expand the NFS interfaces for routines which handle ino's from using ino_t to u64 and then uses the fileid in the nfs_inode instead of i_ino in the inode. The code paths that were updated are in the getattr method and the readdir methods. This should be no real change on 64 bit platforms. Since the ino_t is an unsigned long, it would already be 64 bits wide. Thanx... ps Signed-off-by: Peter Staubach <staubach@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-09NFS: Clean up NFS writeback flush codeTrond Myklebust
The only user of nfs_sync_mapping_range() is nfs_getattr(), which uses it to flush out the entire inode without sending a commit. We therefore replace nfs_sync_mapping_range with a more appropriate helper. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-08-07NFS: Fix put_nfs_open_contextTrond Myklebust
We need to grab the inode->i_lock atomically with the last reference put in order to remove the open context that is being freed from the nfsi->open_files list. Fix by converting the kref to a standard atomic counter and then using atomic_dec_and_lock()... Thanks to Arnd Bergmann for pointing out the problem. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-20mm: Remove slab destructors from kmem_cache_create().Paul Mundt
Slab destructors were no longer supported after Christoph's c59def9f222d44bb7e2f0a559f2906191a0862d7 change. They've been BUGs for both slab and slub, and slob never supported them either. This rips out support for the dtor pointer from kmem_cache_create() completely and fixes up every single callsite in the kernel (there were about 224, not including the slab allocator definitions themselves, or the documentation references). Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-07-11NFSv4: Defer inode revalidation when setting up a delegationTrond Myklebust
Currently we force a synchronous call to __nfs_revalidate_inode() in nfs_inode_set_delegation(). This not only ensures that we cannot call nfs_inode_set_delegation from an asynchronous context, but it also slows down any call to open(). Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-11NFS: Replace NFS_I(inode)->req_lock with inode->i_lockTrond Myklebust
There is no justification for keeping a special spinlock for the exclusive use of the NFS writeback code. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-11NFS: Convert struct nfs_open_context to use a krefTrond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-11NFS: Remove the redundant 'dirty' and 'commit' lists from nfs_inodeTrond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-11NFS: Fix nfs_reval_fsid()Trond Myklebust
We don't need to revalidate the fsid on the root directory. It suffices to revalidate it on the current directory. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-11NFSv4: Ensure that nfs4_do_close() doesn't race with umountTrond Myklebust
nfs4_do_close() does not currently have any way to ensure that the user won't attempt to unmount the partition while the asynchronous RPC call is completing. This again may cause Oopses in nfs_update_inode(). Add a vfsmount argument to nfs4_close_state to ensure that the partition remains mounted while we're closing the file. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-11NFS: Replace vfsmount and dentry in nfs_open_context with struct pathTrond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-05-21Detach sched.h from mm.hAlexey Dobriyan
First thing mm.h does is including sched.h solely for can_do_mlock() inline function which has "current" dereference inside. By dealing with can_do_mlock() mm.h can be detached from sched.h which is good. See below, why. This patch a) removes unconditional inclusion of sched.h from mm.h b) makes can_do_mlock() normal function in mm/mlock.c c) exports can_do_mlock() to not break compilation d) adds sched.h inclusions back to files that were getting it indirectly. e) adds less bloated headers to some files (asm/signal.h, jiffies.h) that were getting them indirectly Net result is: a) mm.h users would get less code to open, read, preprocess, parse, ... if they don't need sched.h b) sched.h stops being dependency for significant number of files: on x86_64 allmodconfig touching sched.h results in recompile of 4083 files, after patch it's only 3744 (-8.3%). Cross-compile tested on all arm defconfigs, all mips defconfigs, all powerpc defconfigs, alpha alpha-up arm i386 i386-up i386-defconfig i386-allnoconfig ia64 ia64-up m68k mips parisc parisc-up powerpc powerpc-up s390 s390-up sparc sparc-up sparc64 sparc64-up um-x86_64 x86_64 x86_64-up x86_64-defconfig x86_64-allnoconfig as well as my two usual configs. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-17Remove SLAB_CTOR_CONSTRUCTORChristoph Lameter
SLAB_CTOR_CONSTRUCTOR is always specified. No point in checking it. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: David Howells <dhowells@redhat.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Steven French <sfrench@us.ibm.com> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Dave Kleikamp <shaggy@austin.ibm.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Anton Altaparmakov <aia21@cantab.net> Cc: Mark Fasheh <mark.fasheh@oracle.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Jan Kara <jack@ucw.cz> Cc: David Chinner <dgc@sgi.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09NFS: Kill the obsolete NFS_PARANOIAJesper Juhl
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-05-07slab allocators: Remove SLAB_DEBUG_INITIAL flagChristoph Lameter
I have never seen a use of SLAB_DEBUG_INITIAL. It is only supported by SLAB. I think its purpose was to have a callback after an object has been freed to verify that the state is the constructor state again? The callback is performed before each freeing of an object. I would think that it is much easier to check the object state manually before the free. That also places the check near the code object manipulation of the object. Also the SLAB_DEBUG_INITIAL callback is only performed if the kernel was compiled with SLAB debugging on. If there would be code in a constructor handling SLAB_DEBUG_INITIAL then it would have to be conditional on SLAB_DEBUG otherwise it would just be dead code. But there is no such code in the kernel. I think SLUB_DEBUG_INITIAL is too problematic to make real use of, difficult to understand and there are easier ways to accomplish the same effect (i.e. add debug code before kfree). There is a related flag SLAB_CTOR_VERIFY that is frequently checked to be clear in fs inode caches. Remove the pointless checks (they would even be pointless without removeal of SLAB_DEBUG_INITIAL) from the fs constructors. This is the last slab flag that SLUB did not support. Remove the check for unimplemented flags from SLUB. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-04-15NFS: Fix an Oops in nfs_setattr()Trond Myklebust
It looks like nfs_setattr() and nfs_rename() also need to test whether the target is a regular file before calling nfs_wb_all()... Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-17[PATCH] nfs: nfs_getattr() can't call nfs_sync_mapping_range() for ↵Trond Myklebust
non-regular files Looks like we need a check in nfs_getattr() for a regular file. It makes no sense to call nfs_sync_mapping_range() on anything else. I think that should fix your problem: it will stop the NFS client from interfering with dirty pages on that inode's mapping. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Olof Johansson <olof@lixom.net> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-13NFS: Cleanup - avoid rereading 'jiffies' more than once in the same routineTrond Myklebust
Micro-optimisations for nfs_fhget() and nfs_wcc_update_inode(). Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-02-13NFS: Fix a wraparound issue with nfsi->cache_change_attributeTrond Myklebust
Fix wraparound issue with nfsi->cache_change_attribute. If it is found to lie in the future, then update it to lie in the past. Patch based on a suggestion by Neil Brown. ..and minor micro-optimisation: avoid reading 'jiffies' more than once in nfs_update_inode(). Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-02-03NFS: nfs_writepages() cleanupTrond Myklebust
Strip out the call to nfs_commit_inode(), and allow that to be done by nfs_write_inode(). Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-01-24[PATCH] NFS: Fix races in nfs_revalidate_mapping()Trond Myklebust
Prevent the call to invalidate_inode_pages2() from racing with file writes by taking the inode->i_mutex across the page cache flush and invalidate. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-12-08[PATCH] nfs: change uses of f_{dentry,vfsmnt} to use f_pathJosef "Jeff" Sipek
Change all the uses of f_{dentry,vfsmnt} to f_path.{dentry,mnt} in the nfs client code. Signed-off-by: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07Merge branch 'master' of /home/trondmy/kernel/linux-2.6/ into merge_linusTrond Myklebust
2006-12-07[PATCH] slab: remove kmem_cache_tChristoph Lameter
Replace all uses of kmem_cache_t with struct kmem_cache. The patch was generated using the following script: #!/bin/sh # # Replace one string by another in all the kernel sources. # set -e for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do quilt add $file sed -e "1,\$s/$1/$2/g" $file >/tmp/$$ mv /tmp/$$ $file quilt refresh done The script was run like this sh replace kmem_cache_t "struct kmem_cache" Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] slab: remove SLAB_KERNELChristoph Lameter
SLAB_KERNEL is an alias of GFP_KERNEL. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-06NFS: cleanup of nfs_sync_inode_wait()Trond Myklebust
Allow callers to directly pass it a struct writeback_control. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-10-20[PATCH] NFS: __nfs_revalidate_inode() can use "inode" before checking it is ↵Chuck Lever
non-NULL The "!inode" check in __nfs_revalidate_inode() occurs well after the first time it is dereferenced, so get rid of it. Coverity: #cid 1372, 1373 Test plan: Code review; recheck with Coverity. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-20[PATCH] NFS: Deal with failure of invalidate_inode_pages2()Trond Myklebust
If invalidate_inode_pages2() fails, then it should in principle just be because the current process was signalled. In that case, we just want to ensure that the inode's page cache remains marked as invalid. Also add a helper to allow the O_DIRECT code to simply mark the page cache as invalid once it is finished writing, instead of calling invalidate_inode_pages2() itself. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-27[PATCH] inode-diet: Eliminate i_blksize from the inode structureTheodore Ts'o
This eliminates the i_blksize field from struct inode. Filesystems that want to provide a per-inode st_blksize can do so by providing their own getattr routine instead of using the generic_fillattr() function. Note that some filesystems were providing pretty much random (and incorrect) values for i_blksize. [bunk@stusta.de: cleanup] [akpm@osdl.org: generic_fillattr() fix] Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-27[PATCH] Really ignore kmem_cache_destroy return valueAlexey Dobriyan
* Rougly half of callers already do it by not checking return value * Code in drivers/acpi/osl.c does the following to be sure: (void)kmem_cache_destroy(cache); * Those who check it printk something, however, slab_error already printed the name of failed cache. * XFS BUGs on failed kmem_cache_destroy which is not the decision low-level filesystem driver should make. Converted to ignore. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-27[PATCH] fs: Removing useless castsPanagiotis Issaris
* Removing useless casts * Removing useless wrapper * Conversion from kmalloc+memset to kzalloc Signed-off-by: Panagiotis Issaris <takis@issaris.org> Acked-by: Dave Kleikamp <shaggy@austin.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-23NFS: add comments clarifying the use of nfs_post_op_update()Chuck Lever
Comments-only change to clarify a detail of the NFS protocol and how it is implemented in Linux. Test plan: None. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-23NFS: Don't invalidate the symlink we just stuffed into the cacheTrond Myklebust
And slight optimisation of nfs_end_data_update(): directories never have delegations anyway. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-23NFS: Add server and volume lists to /procDavid Howells
Make two new proc files available: /proc/fs/nfsfs/servers /proc/fs/nfsfs/volumes The first lists the servers with which we are currently dealing (struct nfs_client), and the second lists the volumes we have on those servers (struct nfs_server). Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-23NFS: Share NFS superblocks per-protocol per-server per-FSIDDavid Howells
The attached patch makes NFS share superblocks between mounts from the same server and FSID over the same protocol. It does this by creating each superblock with a false root and returning the real root dentry in the vfsmount presented by get_sb(). The root dentry set starts off as an anonymous dentry if we don't already have the dentry for its inode, otherwise it simply returns the dentry we already have. We may thus end up with several trees of dentries in the superblock, and if at some later point one of anonymous tree roots is discovered by normal filesystem activity to be located in another tree within the superblock, the anonymous root is named and materialises attached to the second tree at the appropriate point. Why do it this way? Why not pass an extra argument to the mount() syscall to indicate the subpath and then pathwalk from the server root to the desired directory? You can't guarantee this will work for two reasons: (1) The root and intervening nodes may not be accessible to the client. With NFS2 and NFS3, for instance, mountd is called on the server to get the filehandle for the tip of a path. mountd won't give us handles for anything we don't have permission to access, and so we can't set up NFS inodes for such nodes, and so can't easily set up dentries (we'd have to have ghost inodes or something). With this patch we don't actually create dentries until we get handles from the server that we can use to set up their inodes, and we don't actually bind them into the tree until we know for sure where they go. (2) Inaccessible symbolic links. If we're asked to mount two exports from the server, eg: mount warthog:/warthog/aaa/xxx /mmm mount warthog:/warthog/bbb/yyy /nnn We may not be able to access anything nearer the root than xxx and yyy, but we may find out later that /mmm/www/yyy, say, is actually the same directory as the one mounted on /nnn. What we might then find out, for example, is that /warthog/bbb was actually a symbolic link to /warthog/aaa/xxx/www, but we can't actually determine that by talking to the server until /warthog is made available by NFS. This would lead to having constructed an errneous dentry tree which we can't easily fix. We can end up with a dentry marked as a directory when it should actually be a symlink, or we could end up with an apparently hardlinked directory. With this patch we need not make assumptions about the type of a dentry for which we can't retrieve information, nor need we assume we know its place in the grand scheme of things until we actually see that place. This patch reduces the possibility of aliasing in the inode and page caches for inodes that may be accessed by more than one NFS export. It also reduces the number of superblocks required for NFS where there are many NFS exports being used from a server (home directory server + autofs for example). This in turn makes it simpler to do local caching of network filesystems, as it can then be guaranteed that there won't be links from multiple inodes in separate superblocks to the same cache file. Obviously, cache aliasing between different levels of NFS protocol could still be a problem, but at least that gives us another key to use when indexing the cache. This patch makes the following changes: (1) The server record construction/destruction has been abstracted out into its own set of functions to make things easier to get right. These have been moved into fs/nfs/client.c. All the code in fs/nfs/client.c has to do with the management of connections to servers, and doesn't touch superblocks in any way; the remaining code in fs/nfs/super.c has to do with VFS superblock management. (2) The sequence of events undertaken by NFS mount is now reordered: (a) A volume representation (struct nfs_server) is allocated. (b) A server representation (struct nfs_client) is acquired. This may be allocated or shared, and is keyed on server address, port and NFS version. (c) If allocated, the client representation is initialised. The state member variable of nfs_client is used to prevent a race during initialisation from two mounts. (d) For NFS4 a simple pathwalk is performed, walking from FH to FH to find the root filehandle for the mount (fs/nfs/getroot.c). For NFS2/3 we are given the root FH in advance. (e) The volume FSID is probed for on the root FH. (f) The volume representation is initialised from the FSINFO record retrieved on the root FH. (g) sget() is called to acquire a superblock. This may be allocated or shared, keyed on client pointer and FSID. (h) If allocated, the superblock is initialised. (i) If the superblock is shared, then the new nfs_server record is discarded. (j) The root dentry for this mount is looked up from the root FH. (k) The root dentry for this mount is assigned to the vfsmount. (3) nfs_readdir_lookup() creates dentries for each of the entries readdir() returns; this function now attaches disconnected trees from alternate roots that happen to be discovered attached to a directory being read (in the same way nfs_lookup() is made to do for lookup ops). The new d_materialise_unique() function is now used to do this, thus permitting the whole thing to be done under one set of locks, and thus avoiding any race between mount and lookup operations on the same directory. (4) The client management code uses a new debug facility: NFSDBG_CLIENT which is set by echoing 1024 to /proc/net/sunrpc/nfs_debug. (5) Clone mounts are now called xdev mounts. (6) Use the dentry passed to the statfs() op as the handle for retrieving fs statistics rather than the root dentry of the superblock (which is now a dummy). Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>