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2018-02-05ovl: check ERR_PTR() return value from ovl_encode_fh()Amir Goldstein1-0/+3
Another fix for an issue reported by 0-day robot. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Fixes: 8ed5eec9d6c4 ("ovl: encode pure upper file handles") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-02-05ovl: fix regression in fsnotify of overlay merge dirAmir Goldstein1-0/+2
A re-factoring patch in NFS export series has passed the wrong argument to ovl_get_inode() causing a regression in the very recent fix to fsnotify of overlay merge dir. The regression has caused merge directory inodes to be hashed by upper instead of lower real inode, when NFS export and directory indexing is disabled. That caused an inotify watch to become obsolete after directory copy up and drop caches. LTP test inotify07 was improved to catch this regression. The regression also caused multiple redirect dirs to same origin not to be detected on lookup with NFS export disabled. An xfstest was added to cover this case. Fixes: 0aceb53e73be ("ovl: do not pass overlay dentry to ovl_get_inode()") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: wire up NFS export operationsAmir Goldstein1-0/+3
Now that NFS export operations are implemented, enable overlayfs NFS export support if the "nfs_export" feature is enabled. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: lookup indexed ancestor of lower dirAmir Goldstein3-7/+56
ovl_lookup_real() in lower layer walks back lower parents to find the topmost indexed parent. If an indexed ancestor is found before reaching lower layer root, ovl_lookup_real() is called recursively with upper layer to walk back from indexed upper to the topmost connected/hashed upper parent (or up to root). ovl_lookup_real() in upper layer then walks forward to connect the topmost upper overlay dir dentry and ovl_lookup_real() in lower layer continues to walk forward to connect the decoded lower overlay dir dentry. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: lookup connected ancestor of dir in inode cacheAmir Goldstein3-13/+110
Decoding a dir file handle requires walking backward up to layer root and for lower dir also checking the index to see if any of the parents have been copied up. Lookup overlay ancestor dentry in inode/dentry cache by decoded real parents to shortcut looking up all the way back to layer root. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: hash non-indexed dir by upper inode for NFS exportAmir Goldstein1-1/+3
Non-indexed upper dirs are encoded as upper file handles. When NFS export is enabled, hash non-indexed directory inodes by upper inode, so we can find them in inode cache using the decoded upper inode. When NFS export is disabled, directories are not indexed on copy up, so hash non-indexed directory inodes by origin inode, the same hash key that is used before copy up. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: decode pure lower dir file handlesAmir Goldstein1-17/+26
Similar to decoding a pure upper dir file handle, decoding a pure lower dir file handle is implemented by looking an overlay dentry of the same path as the pure lower path and verifying that the overlay dentry's real lower matches the decoded real lower file handle. Unlike the case of upper dir file handle, the lookup of overlay path by lower real path can fail or find a mismatched overlay dentry if any of the lower parents have been copied up and renamed. To address this case we will need to check if any of the lower parents are indexed. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: decode indexed dir file handlesAmir Goldstein3-1/+15
Decoding an indexed dir file handle is done by looking up the file handle in index dir by name and then decoding the upper dir from the index origin file handle. The decoded upper path is used to lookup an overlay dentry of the same path. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: decode lower file handles of unlinked but open filesAmir Goldstein3-2/+38
Lookup overlay inode in cache by origin inode, so we can decode a file handle of an open file even if the index has a whiteout index entry to mark this overlay inode was unlinked. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: decode indexed non-dir file handlesAmir Goldstein1-25/+46
Decoding an indexed non-dir file handle is similar to decoding a lower non-dir file handle, but additionally, we lookup the file handle in index dir by name to find the real upper inode. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: decode lower non-dir file handlesAmir Goldstein3-15/+47
Decoding a lower non-dir file handle is done by decoding the lower dentry from underlying lower fs, finding or allocating an overlay inode that is hashed by the real lower inode and instantiating an overlay dentry with that inode. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: encode lower file handlesAmir Goldstein1-8/+2
For indexed or lower non-dir, encode a non-connectable lower file handle from origin inode. For indexed or lower dir, when ofs->numlower == 1, encode a lower file handle from lower dir. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: copy up before encoding non-connectable dir file handleAmir Goldstein1-4/+49
Decoding a merge dir, whose origin's parent is under a redirected lower dir is not always possible. As a simple aproximation, we do not encode lower dir file handles when overlay has multiple lower layers and origin is below the topmost lower layer. We should later relax this condition and copy up only the parent that is under a redirected lower. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: encode non-indexed upper file handlesAmir Goldstein1-5/+35
We only need to encode origin if there is a chance that the same object was encoded pre copy up and then we need to stay consistent with the same encoding also after copy up. In case a non-pure upper is not indexed, then it was copied up before NFS export support was enabled. In that case, we don't need to worry about staying consistent with pre copy up encoding and we encode an upper file handle. This mitigates the problem that with no index, we cannot find an upper inode from origin inode, so we cannot decode a non-indexed upper from origin file handle. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: decode connected upper dir file handlesAmir Goldstein1-1/+230
Until this change, we decoded upper file handles by instantiating an overlay dentry from the real upper dentry. This is sufficient to handle pure upper files, but insufficient to handle merge/impure dirs. To that end, if decoded real upper dir is connected and hashed, we lookup an overlay dentry with the same path as the real upper dir. If decoded real upper is non-dir, we instantiate a disconnected overlay dentry as before this change. Because ovl_fh_to_dentry() returns a connected overlay dir dentry, exportfs never needs to call get_parent() and get_name() to reconnect an upper overlay dir. Because connectable non-dir file handles are not supported, exportfs will not be able to use fh_to_parent() and get_name() methods to reconnect a disconnected non-dir to its parent. Therefore, the methods get_parent() and get_name() are implemented just to print out a sanity warning and the method fh_to_parent() is implemented to warn the user that using the 'subtree_check' exportfs option is not supported. An alternative approach could have been to implement instantiating of an overlay directory inode from origin/index and implement get_parent() and get_name() by calling into underlying fs operations and them instantiating the overlay parent dir. The reasons for not choosing the get_parent() approach were: - Obtaining a disconnected overlay dir dentry would requires a delicate re-factoring of ovl_lookup() to get a dentry with overlay parent info. It was preferred to avoid doing that re-factoring unless it was proven worthy. - Going down the path of disconnected dir would mean that the (non trivial) code path of d_splice_alias() could be traveled and that meant writing more tests and introduces race cases that are very hard to hit on purpose. Taking the path of connecting overlay dentry by forward lookup is therefore the safe and boring way to avoid surprises. The culprits of the chosen "connected overlay dentry" approach: - We need to take special care to rename of ancestors while connecting the overlay dentry by real dentry path. These subtleties are usually handled by generic exportfs and VFS code. - In a hypothetical workload, we could end up in a loop trying to connect, interrupted by rename and restarting connect forever. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: decode pure upper file handlesAmir Goldstein3-2/+101
Decoding an upper file handle is done by decoding the upper dentry from underlying upper fs, finding or allocating an overlay inode that is hashed by the real upper inode and instantiating an overlay dentry with that inode. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: encode pure upper file handlesAmir Goldstein3-1/+106
Encode overlay file handles as struct ovl_fh containing the file handle encoding of the real upper inode. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: store 'has_upper' and 'opaque' as bit flagsAmir Goldstein5-20/+41
We need to make some room in struct ovl_entry to store information about redirected ancestors for NFS export, so cram two booleans as bit flags. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: copy up of disconnected dentriesAmir Goldstein3-19/+48
With NFS export, some operations on decoded file handles (e.g. open, link, setattr, xattr_set) may call copy up with a disconnected non-dir. In this case, we will copy up lower inode to index dir without linking it to upper dir. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: use d_splice_alias() in place of d_add() in lookupAmir Goldstein1-3/+1
This is required for NFS export. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: do not pass overlay dentry to ovl_get_inode()Amir Goldstein3-12/+12
This is needed for using ovl_get_inode() for decoding file handles for NFS export. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: factor out ovl_get_index_fh() helperAmir Goldstein2-10/+50
The helper is needed to lookup an index by file handle for NFS export. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: whiteout orphan index entries on mountAmir Goldstein2-4/+40
Orphan index entries are non-dir index entries whose union nlink count dropped to zero. With index=on, orphan index entries are removed on mount. With NFS export feature enabled, orphan index entries are replaced with white out index entries to block future open by handle from opening the lower file. When dir index has a stale 'upper' xattr, we assume that the upper dir was removed and we treat the dir index as orphan entry that needs to be whited out or removed. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: whiteout index when union nlink drops to zeroAmir Goldstein3-29/+48
With NFS export feature enabled, when overlay inode nlink drops to zero, instead of removing the index entry, replace it with a whiteout index entry. This is needed for NFS export in order to prevent future open by handle from opening the lower file directly. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: cleanup dir index when dir nlink drops to zeroAmir Goldstein1-3/+3
When non-dir index union nlink drops to zero the non-dir index is cleaned. Do the same for directory type index entries when union directory is removed. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: index directories on copy up for NFS exportAmir Goldstein2-7/+117
With the NFS export feature enabled, all dirs are indexed on copy up. Non-dir files are copied up directly to indexdir and then hardlinked to upper dir. Directories are copied up to indexdir, then an index entry is created in indexdir with 'upper' xattr pointing to the copied up dir and then the copied up dir is moved to upper dir. Directory index is also used for consistency verification, like detecting multiple redirected dirs to the same lower dir on lookup. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: index all non-dir on copy up for NFS exportAmir Goldstein1-0/+4
With the NFS export feature enabled, all non-dir are indexed on copy up. The copy up origin inode of an indexed non-dir can be used as a unique identifier of the overlay object. The full index is also used for consistency verfication, like detecting multiple non-hardlink uppers with the same 'origin' on lookup. Directory index on copy up will be implemented by following patch. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: create ovl_need_index() helperAmir Goldstein3-9/+22
The helper determines which lower file needs to be indexed on copy up and before nlink changes. For index=on, the helper evaluates to true for lower hardlinks. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: cleanup temp index entriesAmir Goldstein1-0/+12
A previous failed attempt to create or whiteout a directory index may leave index entries named '#%x' in the index dir. Cleanup those temp entries on mount instead of failing the mount. In the future, we may drop 'work' dir and use 'index' dir instead. This change is enough for cleaning up copy up leftovers 'from the future', but it is not enough for cleaning up rmdir leftovers 'from the future' (i.e. temp dir containing whiteouts). Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: verify directory index entries on mountAmir Goldstein1-32/+93
Directory index entries should have 'upper' xattr pointing to the real upper dir. Verifying that the upper dir file handle is not stale is expensive, so only verify stale directory index entries on mount if NFS export feature is enabled. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: verify whiteout index entries on mountAmir Goldstein1-8/+13
Whiteout index entries are used as an indication that an exported overlay file handle should be treated as stale (i.e. after unlink of the overlay inode). Check on mount that whiteout index entries have a name that looks like a valid file handle and cleanup invalid index entries. For whiteout index entries, do not check that they also have valid origin fh and nlink xattr, because those xattr do not exist for a whiteout index entry. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: use directory index entries for consistency verificationAmir Goldstein3-11/+58
A directory index is a directory type entry in index dir with a "trusted.overlay.upper" xattr containing an encoded ovl_fh of the merge directory upper dir inode. On lookup of non-dir files, lower file is followed by origin file handle. On lookup of dir entries, lower dir is found by name and then compared to origin file handle. We only trust dir index if we verified that lower dir matches origin file handle, otherwise index may be inconsistent and we ignore it. If we find an indexed non-upper dir or an indexed merged dir, whose index 'upper' xattr points to a different upper dir, that means that the lower directory may be also referenced by another upper dir via redirect, so we fail the lookup on inconsistency error. To be consistent with directory index entries format, the association of index dir to upper root dir, that was stored by older kernels in "trusted.overlay.origin" xattr is now stored in "trusted.overlay.upper" xattr. This also serves as an indication that overlay was mounted with a kernel that support index directory entries. For backward compatibility, if an 'origin' xattr exists on the index dir we also verify it on mount. Directory index entries are going to be used for NFS export. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: unbless lower st_ino of unverified originAmir Goldstein1-4/+12
On a malformed overlay, several redirected dirs can point to the same dir on a lower layer. This presents a similar challenge as broken hardlinks, because different objects in the overlay can return the same st_ino/st_dev pair from stat(2). For broken hardlinks, we do not provide constant st_ino on copy up to avoid this inconsistency. When NFS export feature is enabled, apply the same logic to files and directories with unverified lower origin. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: verify stored origin fh matches lower dirAmir Goldstein1-0/+12
When the NFS export feature is enabled, overlayfs implicitly enables the feature "verify_lower". When the "verify_lower" feature is enabled, a directory inode found in lower layer by name or by redirect_dir is verified against the file handle of the copy up origin that is stored in the upper layer. This introduces a change of behavior for the case of lower layer modification while overlay is offline. A lower directory created or moved offline under an exisitng upper directory, will not be merged with that upper directory. The NFS export feature should not be used after copying layers, because the new lower directory inodes would fail verification and won't be merged with upper directories. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: add support for "nfs_export" configurationAmir Goldstein5-5/+85
Introduce the "nfs_export" config, module and mount options. The NFS export feature depends on the "index" feature and enables two implicit overlayfs features: "index_all" and "verify_lower". The "index_all" feature creates an index on copy up of every file and directory. The "verify_lower" feature uses the full index to detect overlay filesystems inconsistencies on lookup, like redirect from multiple upper dirs to the same lower dir. NFS export can be enabled for non-upper mount with no index. However, because lower layer redirects cannot be verified with the index, enabling NFS export support on an overlay with no upper layer requires turning off redirect follow (e.g. "redirect_dir=nofollow"). The full index may incur some overhead on mount time, especially when verifying that lower directory file handles are not stale. NFS export support, full index and consistency verification will be implemented by following patches. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: update documentation of inodes index featureAmir Goldstein1-6/+3
Document that inode index feature solves breaking hard links on copy up. Simplify Kconfig backward compatibility disclaimer. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: generalize ovl_verify_origin() and helpersAmir Goldstein4-30/+38
Remove the "origin" language from the functions that handle set, get and verify of "origin" xattr and pass the xattr name as an argument. The same helpers are going to be used for NFS export to get, get and verify the "upper" xattr for directory index entries. ovl_verify_origin() is now a helper used only to verify non upper file handle stored in "origin" xattr of upper inode. The upper root dir file handle is still stored in "origin" xattr on the index dir for backward compatibility. This is going to be changed by the patch that adds directory index entries support. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: simplify arguments to ovl_check_origin_fh()Amir Goldstein4-30/+24
Pass the fs instance with lower_layers array instead of the dentry lowerstack array to ovl_check_origin_fh(), because the dentry members of lowerstack play no role in this helper. This change simplifies the argument list of ovl_check_origin(), ovl_cleanup_index() and ovl_verify_index(). Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: factor out ovl_check_origin_fh()Amir Goldstein1-50/+92
Re-factor ovl_check_origin() and ovl_get_origin(), so origin fh xattr is read from upper inode only once during lookup with multiple lower layers and only once when verifying index entry origin. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: store layer index in ovl_layerAmir Goldstein3-16/+4
Store the fs root layer index inside ovl_layer struct, so we can get the root fs layer index from merge dir lower layer instead of find it with ovl_find_layer() helper. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: force r/o mount when index dir creation failsAmir Goldstein1-3/+9
When work dir creation fails, a warning is emitted and overlay is mounted r/o. Trying to remount r/w will fail with no work dir. When index dir creation fails, the same warning is emitted and overlay is mounted r/o, but trying to remount r/w will succeed. This may cause unintentional corruption of filesystem consistency. Adjust the behavior of index dir creation failure to that of work dir creation failure and do not allow to remount r/w. User needs to state an explicitly intention to work without an index by mounting with option 'index=off' to allow r/w mount with no index dir. When mounting with option 'index=on' and no 'upperdir', index is implicitly disabled, so do not warn about no file handle support. The issue was introduced with inodes index feature in v4.13, but this patch will not apply cleanly before ovl_fill_super() re-factoring in v4.15. Fixes: 02bcd1577400 ("ovl: introduce the inodes index dir feature") Cc: <stable@vger.kernel.org> #v4.13 Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: disable index when no xattr supportAmir Goldstein1-1/+2
Overlayfs falls back to index=off if lower/upper fs does not support file handles. Do the same if upper fs does not support xattr. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-24ovl: fix inconsistent d_ino for legacy merge dirAmir Goldstein3-2/+37
For a merge dir that was copied up before v4.12 or that was hand crafted offline (e.g. mkdir {upper/lower}/dir), upper dir does not contain the 'trusted.overlay.origin' xattr. In that case, stat(2) on the merge dir returns the lower dir st_ino, but getdents(2) returns the upper dir d_ino. After this change, on merge dir lookup, missing origin xattr on upper dir will be fixed and 'impure' xattr will be fixed on parent of the legacy merge dir. Suggested-by: zhangyi (F) <yi.zhang@huawei.com> Reviewed-by: zhangyi (F) <yi.zhang@huawei.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-19ovl: take mnt_want_write() for removing impure xattrAmir Goldstein1-2/+9
The optimization in ovl_cache_get_impure() that tries to remove an unneeded "impure" xattr needs to take mnt_want_write() on upper fs. Fixes: 4edb83bb1041 ("ovl: constant d_ino for non-merge dirs") Cc: <stable@vger.kernel.org> #v4.14 Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-19ovl: take mnt_want_write() for work/index dir setupAmir Goldstein1-8/+17
There are several write operations on upper fs not covered by mnt_want_write(): - test set/remove OPAQUE xattr - test create O_TMPFILE - set ORIGIN xattr in ovl_verify_origin() - cleanup of index entries in ovl_indexdir_cleanup() Some of these go way back, but this patch only applies over the v4.14 re-factoring of ovl_fill_super(). Cc: <stable@vger.kernel.org> #v4.14 Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-19ovl: fix another overlay: warning prefixAmir Goldstein1-1/+2
Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-19ovl: take lower dir inode mutex outside upper sb_writers lockAmir Goldstein3-65/+58
The functions ovl_lower_positive() and ovl_check_empty_dir() both take inode mutex on the real lower dir under ovl_want_write() which takes the upper_mnt sb_writers lock. While this is not a clear locking order or layering violation, it creates an undesired lock dependency between two unrelated layers for no good reason. This lock dependency materializes to a false(?) positive lockdep warning when calling rmdir() on a nested overlayfs, where both nested and underlying overlayfs both use the same fs type as upper layer. rmdir() on the nested overlayfs creates the lock chain: sb_writers of upper_mnt (e.g. tmpfs) in ovl_do_remove() ovl_i_mutex_dir_key[] of lower overlay dir in ovl_lower_positive() rmdir() on the underlying overlayfs creates the lock chain in reverse order: ovl_i_mutex_dir_key[] of lower overlay dir in vfs_rmdir() sb_writers of nested upper_mnt (e.g. tmpfs) in ovl_do_remove() To rid of the unneeded locking dependency, move both ovl_lower_positive() and ovl_check_empty_dir() to before ovl_want_write() in rmdir() and rename() implementation. This change spreads the pieces of ovl_check_empty_and_clear() directly inside the rmdir()/rename() implementations so the helper is no longer needed and removed. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-19ovl: fix failure to fsync lower dirAmir Goldstein1-1/+5
As a writable mount, it is not expected for overlayfs to return EINVAL/EROFS for fsync, even if dir/file is not changed. This commit fixes the case of fsync of directory, which is easier to address, because overlayfs already implements fsync file operation for directories. The problem reported by Raphael is that new PostgreSQL 10.0 with a database in overlayfs where lower layer in squashfs fails to start. The failure is due to fsync error, when PostgreSQL does fsync on all existing db directories on startup and a specific directory exists lower layer with no changes. Reported-by: Raphael Hertzog <raphael@ouaza.com> Cc: <stable@vger.kernel.org> # v3.18 Signed-off-by: Amir Goldstein <amir73il@gmail.com> Tested-by: Raphaƫl Hertzog <hertzog@debian.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-19ovl: hash directory inodes for fsnotifyAmir Goldstein3-13/+31
fsnotify pins a watched directory inode in cache, but if directory dentry is released, new lookup will allocate a new dentry and a new inode. Directory events will be notified on the new inode, while fsnotify listener is watching the old pinned inode. Hash all directory inodes to reuse the pinned inode on lookup. Pure upper dirs are hashes by real upper inode, merge and lower dirs are hashed by real lower inode. The reference to lower inode was being held by the lower dentry object in the overlay dentry (oe->lowerstack[0]). Releasing the overlay dentry may drop lower inode refcount to zero. Add a refcount on behalf of the overlay inode to prevent that. As a by-product, hashing directory inodes also detects multiple redirected dirs to the same lower dir and uncovered redirected dir target on and returns -ESTALE on lookup. The reported issue dates back to initial version of overlayfs, but this patch depends on ovl_inode code that was introduced in kernel v4.13. Cc: <stable@vger.kernel.org> #v4.13 Reported-by: Niklas Cassel <niklas.cassel@axis.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Tested-by: Niklas Cassel <niklas.cassel@axis.com>
2017-12-14ovl: fix overlay: warning prefixAmir Goldstein2-2/+3
Conform two stray warning messages to the standard overlayfs: prefix. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>