user/sven/linux.git/include/linux/dcache.h, branch v4.1.25

use ->d_seq to get coherency between ->d_inode and ->d_flags

2016-03-09T18:15:20Z

[ Upstream commit a528aca7f359f4b0b1d72ae406097e491a5ba9ea ] Games with ordering and barriers are way too brittle. Just bump ->d_seq before and after updating ->d_inode and ->d_flags type bits, so that verifying ->d_seq would guarantee they are coherent. Cc: stable@vger.kernel.org # v3.13+ Signed-off-by: Al Viro Signed-off-by: Sasha Levin

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

2015-10-22T21:43:26Z

commit 4bacc9c9234c7c8eec44f5ed4e960d9f96fa0f01 upstream. 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 Cc: "Kamata, Munehisa" Signed-off-by: Greg Kroah-Hartman

VFS: Impose ordering on accesses of d_inode and d_flags

2015-04-15T19:05:28Z

Impose ordering on accesses of d_inode and d_flags to avoid the need to do this: if (!dentry->d_inode || d_is_negative(dentry)) { when this: if (d_is_negative(dentry)) { should suffice. This check is especially problematic if a dentry can have its type field set to something other than DENTRY_MISS_TYPE when d_inode is NULL (as in unionmount). What we really need to do is stick a write barrier between setting d_inode and setting d_flags and a read barrier between reading d_flags and reading d_inode. Signed-off-by: David Howells Signed-off-by: Al Viro

VFS: Add owner-filesystem positive/negative dentry checks

2015-04-15T19:04:42Z

Supply two functions to test whether a filesystem's own dentries are positive or negative (d_really_is_positive() and d_really_is_negative()). The problem is that the DCACHE_ENTRY_TYPE field of dentry->d_flags may be overridden by the union part of a layered filesystem and isn't thus necessarily indicative of the type of dentry. Normally, this would involve a negative dentry (ie. ->d_inode == NULL) having ->d_layer.lower pointed to a lower layer dentry, DCACHE_PINNING_LOWER set and the DCACHE_ENTRY_TYPE field set to something other than DCACHE_MISS_TYPE - but it could also involve, say, a DCACHE_SPECIAL_TYPE being overridden to DCACHE_WHITEOUT_TYPE if a 0,0 chardev is detected in the top layer. However, inside a filesystem, when that fs is looking at its own dentries, it probably wants to know if they are really negative or not - and doesn't care about the fallthrough bits used by the union. To this end, a filesystem should normally use d_really_is_positive/negative() when looking at its own dentries rather than d_is_positive/negative() and should use d_inode() to get at the inode. Anyone looking at someone else's dentries (this includes pathwalk) should use d_is_xxx() and d_backing_inode(). Signed-off-by: David Howells Signed-off-by: Al Viro

VFS: Split DCACHE_FILE_TYPE into regular and special types

2015-02-22T16:38:38Z

Split DCACHE_FILE_TYPE into DCACHE_REGULAR_TYPE (dentries representing regular files) and DCACHE_SPECIAL_TYPE (representing blockdev, chardev, FIFO and socket files). d_is_reg() and d_is_special() are added to detect these subtypes and d_is_file() is left as the union of the two. This allows a number of places that use S_ISREG(dentry->d_inode->i_mode) to use d_is_reg(dentry) instead. Signed-off-by: David Howells Signed-off-by: Al Viro

VFS: Add a fallthrough flag for marking virtual dentries

2015-02-22T16:38:38Z

Add a DCACHE_FALLTHRU flag to indicate that, in a layered filesystem, this is a virtual dentry that covers another one in a lower layer that should be used instead. This may be recorded on medium if directory integration is stored there. The flag can be set with d_set_fallthru() and tested with d_is_fallthru(). Original-author: Valerie Aurora Signed-off-by: David Howells Signed-off-by: Al Viro

VFS: Add a whiteout dentry type

2015-02-22T16:38:37Z

Add DCACHE_WHITEOUT_TYPE and provide a d_is_whiteout() accessor function. A d_is_miss() accessor is also added for ordinary cache misses and d_is_negative() is modified to indicate either an ordinary miss or an enforced miss (whiteout). Signed-off-by: David Howells Signed-off-by: Al Viro

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

2015-02-22T16:38:15Z

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

kill d_validate()

2015-01-26T04:16:26Z

no users left Signed-off-by: Al Viro

switch d_materialise_unique() users to d_splice_alias()

2014-11-19T18:01:20Z

Signed-off-by: Al Viro