user/sven/linux.git/include/linux/dcache.h, branch v3.18.84

dentry name snapshots

2017-08-11T16:30:11Z

commit 49d31c2f389acfe83417083e1208422b4091cd9e upstream. take_dentry_name_snapshot() takes a safe snapshot of dentry name; if the name is a short one, it gets copied into caller-supplied structure, otherwise an extra reference to external name is grabbed (those are never modified). In either case the pointer to stable string is stored into the same structure. dentry must be held by the caller of take_dentry_name_snapshot(), but may be freely dropped afterwards - the snapshot will stay until destroyed by release_dentry_name_snapshot(). Intended use: struct name_snapshot s; take_dentry_name_snapshot(&s, dentry); ... access s.name ... release_dentry_name_snapshot(&s); Replaces fsnotify_oldname_...(), gets used in fsnotify to obtain the name to pass down with event. Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman

overlayfs: Make f_path always point to the overlay and f_inode to the underlay

2015-10-28T02:14:24Z

[ Upstream commit 4bacc9c9234c7c8eec44f5ed4e960d9f96fa0f01 ] Make file->f_path always point to the overlay dentry so that the path in /proc/pid/fd is correct and to ensure that label-based LSMs have access to the overlay as well as the underlay (path-based LSMs probably don't need it). Using my union testsuite to set things up, before the patch I see: [root@andromeda union-testsuite]# bash 5 /a/foo107 [root@andromeda union-testsuite]# stat /mnt/a/foo107 ... Device: 23h/35d Inode: 13381 Links: 1 ... [root@andromeda union-testsuite]# stat -L /proc/$$/fd/5 ... Device: 23h/35d Inode: 13381 Links: 1 ... After the patch: [root@andromeda union-testsuite]# bash 5 /mnt/a/foo107 [root@andromeda union-testsuite]# stat /mnt/a/foo107 ... Device: 23h/35d Inode: 40346 Links: 1 ... [root@andromeda union-testsuite]# stat -L /proc/$$/fd/5 ... Device: 23h/35d Inode: 40346 Links: 1 ... Note the change in where /proc/$$/fd/5 points to in the ls command. It was pointing to /a/foo107 (which doesn't exist) and now points to /mnt/a/foo107 (which is correct). The inode accessed, however, is the lower layer. The union layer is on device 25h/37d and the upper layer on 24h/36d. Signed-off-by: David Howells Signed-off-by: Al Viro Signed-off-by: Sasha Levin

VFS: Introduce inode-getting helpers for layered/unioned fs environments

2015-10-28T02:14:23Z

[ Upstream commit 155e35d4daa804582f75acaa2c74ec797a89c615 ] Introduce some function for getting the inode (and also the dentry) in an environment where layered/unioned filesystems are in operation. The problem is that we have places where we need *both* the union dentry and the lower source or workspace inode or dentry available, but we can only have a handle on one of them. Therefore we need to derive the handle to the other from that. The idea is to introduce an extra field in struct dentry that allows the union dentry to refer to and pin the lower dentry. Signed-off-by: David Howells Signed-off-by: Al Viro Signed-off-by: Sasha Levin

move d_rcu from overlapping d_child to overlapping d_alias

2014-12-16T17:39:06Z

commit 946e51f2bf37f1656916eb75bd0742ba33983c28 upstream. Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman

don't need that forward declaration of struct nameidata in dcache.h anymore

2014-10-12T21:09:06Z

Signed-off-by: Al Viro

take dname_external() into fs/dcache.c

2014-10-12T21:09:05Z

never used outside and it's too low-level for legitimate uses outside of fs/dcache.c anyway Signed-off-by: Al Viro

vfs: Make d_invalidate return void

2014-10-09T06:38:57Z

Now that d_invalidate can no longer fail, stop returning a useless return code. For the few callers that checked the return code update remove the handling of d_invalidate failure. Reviewed-by: Miklos Szeredi Signed-off-by: "Eric W. Biederman" Signed-off-by: Al Viro

vfs: Merge check_submounts_and_drop and d_invalidate

2014-10-09T06:38:57Z

Now that d_invalidate is the only caller of check_submounts_and_drop, expand check_submounts_and_drop inline in d_invalidate. Reviewed-by: Miklos Szeredi Signed-off-by: "Eric W. Biederman" Signed-off-by: Al Viro

vfs: avoid non-forwarding large load after small store in path lookup

2014-09-15T00:28:32Z

The performance regression that Josef Bacik reported in the pathname lookup (see commit 99d263d4c5b2 "vfs: fix bad hashing of dentries") made me look at performance stability of the dcache code, just to verify that the problem was actually fixed. That turned up a few other problems in this area. There are a few cases where we exit RCU lookup mode and go to the slow serializing case when we shouldn't, Al has fixed those and they'll come in with the next VFS pull. But my performance verification also shows that link_path_walk() turns out to have a very unfortunate 32-bit store of the length and hash of the name we look up, followed by a 64-bit read of the combined hash_len field. That screws up the processor store to load forwarding, causing an unnecessary hickup in this critical routine. It's caused by the ugly calling convention for the "hash_name()" function, and easily fixed by just making hash_name() fill in the whole 'struct qstr' rather than passing it a pointer to just the hash value. With that, the profile for this function looks much smoother. Signed-off-by: Linus Torvalds

dcache: d_obtain_alias callers don't all want DISCONNECTED

2014-08-07T18:40:10Z

There are a few d_obtain_alias callers that are using it to get the root of a filesystem which may already have an alias somewhere else. This is not the same as the filehandle-lookup case, and none of them actually need DCACHE_DISCONNECTED set. It isn't really a serious problem, but it would really be clearer if we reserved DCACHE_DISCONNECTED for those cases where it's actually needed. In the btrfs case this was causing a spurious printk from nfsd/nfsfh.c:fh_verify when it found an unexpected DCACHE_DISCONNECTED dentry. Josef worked around this by unsetting DCACHE_DISCONNECTED manually in 3a0dfa6a12e "Btrfs: unset DCACHE_DISCONNECTED when mounting default subvol", and this replaces that workaround. Cc: Josef Bacik Signed-off-by: J. Bruce Fields Signed-off-by: Al Viro