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path: root/fs/overlayfs/readdir.c (follow)
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2015-06-22ovl: lookup whiteouts outside iterate_dir()Miklos Szeredi1-28/+49
If jffs2 can deadlock on overlayfs readdir because it takes the same lock on ->iterate() as in ->lookup(). Fix by moving whiteout checking outside iterate_dir(). Optimized by collecting potential whiteouts (DT_CHR) in a temporary list and if non-empty iterating throug these and checking for a 0/0 chardev. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Fixes: 49c21e1cacd7 ("ovl: check whiteout while reading directory") Reported-by: Roman Yeryomin <leroi.lists@gmail.com>
2015-02-20Merge branch 'overlayfs-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs into for-nextAl Viro1-106/+75
2015-01-09ovl: discard independent cursor in readdir()hujianyang1-24/+14
Since the ovl_dir_cache is stable during a directory reading, the cursor of struct ovl_dir_file don't need to be an independent entry in the list of a merged directory. This patch changes *cursor* to a pointer which points to the entry in the ovl_dir_cache. After this, we don't need to check *is_cursor* either. Signed-off-by: hujianyang <hujianyang@huawei.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: check whiteout on lowest layer as wellMiklos Szeredi1-39/+40
Not checking whiteouts on lowest layer was an optimization (there's nothing to white out there), but it could result in inconsitent behavior when a layer previously used as upper/middle is later used as lowest. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: multi-layer readdirMiklos Szeredi1-22/+21
If multiple lower layers exist, merge them as well in readdir according to the same rules as merging upper with lower. I.e. take whiteouts and opaque directories into account on all but the lowers layer. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: make path-type a bitmapMiklos Szeredi1-5/+5
OVL_PATH_PURE_UPPER -> __OVL_PATH_UPPER | __OVL_PATH_PURE OVL_PATH_UPPER -> __OVL_PATH_UPPER OVL_PATH_MERGE -> __OVL_PATH_UPPER | __OVL_PATH_MERGE OVL_PATH_LOWER -> 0 Multiple R/O layers will allow __OVL_PATH_MERGE without __OVL_PATH_UPPER. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: check whiteout while reading directoryMiklos Szeredi1-49/+28
Don't make a separate pass for checking whiteouts, since we can do it while reading the upper directory. This will make it easier to handle multiple layers. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-08Merge branch 'iov_iter' into for-nextAl Viro1-24/+17
2014-11-20ovl: ovl_dir_fsync() cleanupMiklos Szeredi1-2/+2
Check against !OVL_PATH_LOWER instead of OVL_PATH_MERGE. For a copied up directory the two are currently equivalent. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-11-20ovl: pass dentry into ovl_dir_read_merged()Miklos Szeredi1-21/+14
Pass dentry into ovl_dir_read_merged() insted of upperpath and lowerpath. This cleans up callers and paves the way for multi-layer directory reads. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-11-05ovl: don't poison cursorMiklos Szeredi1-1/+1
ovl_cache_put() can be called from ovl_dir_reset() if the cache needs to be rebuilt. We did list_del() on the cursor, which results in an Oops on the poisoned pointer in ovl_seek_cursor(). Reported-by: Jordi Pujol Palomer <jordipujolp@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Tested-by: Jordi Pujol Palomer <jordipujolp@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-10-31vfs: make first argument of dir_context.actor typedMiklos Szeredi1-3/+5
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-10-31ovl: initialize ->is_cursorMiklos Szeredi1-0/+1
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-10-28overlayfs: fix lockdep misannotationMiklos Szeredi1-1/+1
In an overlay directory that shadows an empty lower directory, say /mnt/a/empty102, do: touch /mnt/a/empty102/x unlink /mnt/a/empty102/x rmdir /mnt/a/empty102 It's actually harmless, but needs another level of nesting between I_MUTEX_CHILD and I_MUTEX_NORMAL. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Tested-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-10-28ovl: fix check for cursorMiklos Szeredi1-5/+6
ovl_cache_entry.name is now an array not a pointer, so it makes no sense test for it being NULL. Detected by coverity. From: Miklos Szeredi <mszeredi@suse.cz> Fixes: 68bf8611076a ("overlayfs: make ovl_cache_entry->name an array instead of +pointer") Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-10-28overlayfs: barriers for opening upper-layer directoryAl Viro1-1/+2
make sure that a) all stores done by opening struct file don't leak past storing the reference in od->upperfile b) the lockless side has read dependency barrier Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-10-24overlayfs: embed middle into overlay_readdir_dataAl Viro1-7/+5
same story... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-10-24overlayfs: embed root into overlay_readdir_dataAl Viro1-6/+5
no sense having it a pointer - all instances have it pointing to local variable in the same stack frame Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-10-24overlayfs: make ovl_cache_entry->name an array instead of pointerAl Viro1-6/+5
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-10-24overlayfs: don't hold ->i_mutex over opening the real directoryAl Viro1-6/+13
just use it to serialize the assignment Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-10-24overlay filesystemMiklos Szeredi1-0/+587
Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
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