linux/fs/nfs/dir.c, branch v2.6.29-rc7

optimize attribute timeouts for "noac" and "actimeo=0"

2008-12-23T20:21:56Z

Hi. I've been looking at a bugzilla which describes a problem where a customer was advised to use either the "noac" or "actimeo=0" mount options to solve a consistency problem that they were seeing in the file attributes. It turned out that this solution did not work reliably for them because sometimes, the local attribute cache was believed to be valid and not timed out. (With an attribute cache timeout of 0, the cache should always appear to be timed out.) In looking at this situation, it appears to me that the problem is that the attribute cache timeout code has an off-by-one error in it. It is assuming that the cache is valid in the region, [read_cache_jiffies, read_cache_jiffies + attrtimeo]. The cache should be considered valid only in the region, [read_cache_jiffies, read_cache_jiffies + attrtimeo). With this change, the options, "noac" and "actimeo=0", work as originally expected. This problem was previously addressed by special casing the attrtimeo == 0 case. However, since the problem is only an off- by-one error, the cleaner solution is address the off-by-one error and thus, not require the special case. Thanx... ps Signed-off-by: Peter Staubach Signed-off-by: Trond Myklebust

NFS: Use delegations to optimise ACCESS calls

2008-12-23T20:21:55Z

Signed-off-by: Trond Myklebust

NFSv4: Ensure that we set the verifier when revalidating delegated dentries

2008-12-23T20:21:54Z

This ensures that we don't have to look up the dentry again after we return the delegation if we know that the directory didn't change. Signed-off-by: Trond Myklebust

NFSv4: Clean up is_atomic_open()

2008-12-23T20:21:54Z

Signed-off-by: Trond Myklebust

[PATCH] move executable checking into ->permission()

2008-10-23T09:13:25Z

For execute permission on a regular files we need to check if file has any execute bits at all, regardless of capabilites. This check is normally performed by generic_permission() but was also added to the case when the filesystem defines its own ->permission() method. In the latter case the filesystem should be responsible for performing this check. Move the check from inode_permission() inside filesystems which are not calling generic_permission(). Create a helper function execute_ok() that returns true if the inode is a directory or if any execute bits are present in i_mode. Also fix up the following code: - coda control file is never executable - sysctl files are never executable - hfs_permission seems broken on MAY_EXEC, remove - hfsplus_permission is eqivalent to generic_permission(), remove Signed-off-by: Miklos Szeredi

[PATCH] make O_EXCL in nd->intent.flags visible in nd->flags

2008-10-23T09:12:56Z

New flag: LOOKUP_EXCL. Set before doing the final step of pathname resolution on the paths that have LOOKUP_CREATE and O_EXCL. Signed-off-by: Al Viro

vmscan: split LRU lists into anon & file sets

2008-10-20T15:50:25Z

Split the LRU lists in two, one set for pages that are backed by real file systems ("file") and one for pages that are backed by memory and swap ("anon"). The latter includes tmpfs. The advantage of doing this is that the VM will not have to scan over lots of anonymous pages (which we generally do not want to swap out), just to find the page cache pages that it should evict. This patch has the infrastructure and a basic policy to balance how much we scan the anon lists and how much we scan the file lists. The big policy changes are in separate patches. [lee.schermerhorn@hp.com: collect lru meminfo statistics from correct offset] [kosaki.motohiro@jp.fujitsu.com: prevent incorrect oom under split_lru] [kosaki.motohiro@jp.fujitsu.com: fix pagevec_move_tail() doesn't treat unevictable page] [hugh@veritas.com: memcg swapbacked pages active] [hugh@veritas.com: splitlru: BDI_CAP_SWAP_BACKED] [akpm@linux-foundation.org: fix /proc/vmstat units] [nishimura@mxp.nes.nec.co.jp: memcg: fix handling of shmem migration] [kosaki.motohiro@jp.fujitsu.com: adjust Quicklists field of /proc/meminfo] [kosaki.motohiro@jp.fujitsu.com: fix style issue of get_scan_ratio()] Signed-off-by: Rik van Riel Signed-off-by: Lee Schermerhorn Signed-off-by: KOSAKI Motohiro Signed-off-by: Hugh Dickins Signed-off-by: Daisuke Nishimura Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

NFS: Fix a resolution problem with nfs_inode->cache_change_attribute

2008-10-14T23:24:50Z

The cache_change_attribute is used to decide whether or not a directory has changed, in which case we may need to look it up again. Again, the use of 'jiffies' leads to an issue of resolution. Once again, the fix is to change nfs_inode->cache_change_attribute, and just make it a simple counter. Signed-off-by: Trond Myklebust

NFS: Fix the resolution problem with nfs_inode_attrs_need_update()

2008-10-14T23:23:17Z

It appears that 'jiffies' timestamps do not have high enough resolution for nfs_inode_attrs_need_update(). One problem is that a GETATTR can be launched within < 1 jiffy of the last operation that updated the attribute. Another problem is that RPC calls can take < 1 jiffy to execute. We can fix this by switching the variables to use a simple global counter that gets incremented every time we start another GETATTR call. Signed-off-by: Trond Myklebust

NFS: Add options for finer control of the lookup cache

2008-10-07T21:22:20Z

Add the flag NFS_MOUNT_LOOKUP_CACHE_NONEG to turn off the caching of negative dentries. In reality what we do is to force nfs_lookup_revalidate() to always discard negative dentries. Add the flag NFS_MOUNT_LOOKUP_CACHE_NONE for enforcing stricter revalidation of dentries. It forces the revalidate code to always do a lookup instead of just checking the cached mtime of the parent directory. Signed-off-by: Trond Myklebust