kernel/git/stable/linux.git/fs/f2fs/dir.c, branch linux-5.5.y

f2fs: fix race conditions in ->d_compare() and ->d_hash()

2020-02-11T12:36:55+00:00

commit 80f2388afa6ef985f9c5c228e36705c4d4db4756 upstream. Since ->d_compare() and ->d_hash() can be called in RCU-walk mode, ->d_parent and ->d_inode can be concurrently modified, and in particular, ->d_inode may be changed to NULL. For f2fs_d_hash() this resulted in a reproducible NULL dereference if a lookup is done in a directory being deleted, e.g. with: int main() { if (fork()) { for (;;) { mkdir("subdir", 0700); rmdir("subdir"); } } else { for (;;) access("subdir/file", 0); } } ... or by running the 't_encrypted_d_revalidate' program from xfstests. Both repros work in any directory on a filesystem with the encoding feature, even if the directory doesn't actually have the casefold flag. I couldn't reproduce a crash in f2fs_d_compare(), but it appears that a similar crash is possible there. Fix these bugs by reading ->d_parent and ->d_inode using READ_ONCE() and falling back to the case sensitive behavior if the inode is NULL. Reported-by: Al Viro Fixes: 2c2eb7a300cd ("f2fs: Support case-insensitive file name lookups") Cc: # v5.4+ Signed-off-by: Eric Biggers Signed-off-by: Jaegeuk Kim Signed-off-by: Greg Kroah-Hartman

f2fs: fix dcache lookup of !casefolded directories

2020-02-11T12:36:55+00:00

commit 5515eae647426169e4b7969271fb207881eba7f6 upstream. Do the name comparison for non-casefolded directories correctly. This is analogous to ext4's commit 66883da1eee8 ("ext4: fix dcache lookup of !casefolded directories"). Fixes: 2c2eb7a300cd ("f2fs: Support case-insensitive file name lookups") Cc: # v5.4+ Signed-off-by: Eric Biggers Signed-off-by: Jaegeuk Kim Signed-off-by: Greg Kroah-Hartman

f2fs: show f2fs instance in printk_ratelimited

2019-11-19T22:41:21+00:00

As Eric mentioned, bare printk{,_ratelimited} won't show which filesystem instance these message is coming from, this patch tries to show fs instance with sb->s_id field in all places we missed before. Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: fix to avoid accessing uninitialized field of inode page in is_alive()

2019-09-16T15:38:26+00:00

If inode is newly created, inode page may not synchronize with inode cache, so fields like .i_inline or .i_extra_isize could be wrong, in below call path, we may access such wrong fields, result in failing to migrate valid target block. Thread A Thread B - f2fs_create - f2fs_add_link - f2fs_add_dentry - f2fs_init_inode_metadata - f2fs_add_inline_entry - f2fs_new_inode_page - f2fs_put_page : inode page wasn't updated with inode cache - gc_data_segment - is_alive - f2fs_get_node_page - datablock_addr - offset_in_addr : access uninitialized fields Fixes: 7a2af766af15 ("f2fs: enhance on-disk inode structure scalability") Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: optimize case-insensitive lookups

2019-09-06T23:18:12+00:00

This patch ports below casefold enhancement patch from ext4 to f2fs commit 3ae72562ad91 ("ext4: optimize case-insensitive lookups") Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: introduce f2fs_match_name() for cleanup

2019-08-23T14:57:15+00:00

This patch introduces f2fs_match_name() for cleanup. BTW, it avoids to fallback to normal comparison once it doesn't match casefolded name. Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: Support case-insensitive file name lookups

2019-08-23T14:57:13+00:00

Modeled after commit b886ee3e778e ("ext4: Support case-insensitive file name lookups") """ This patch implements the actual support for case-insensitive file name lookups in f2fs, based on the feature bit and the encoding stored in the superblock. A filesystem that has the casefold feature set is able to configure directories with the +F (F2FS_CASEFOLD_FL) attribute, enabling lookups to succeed in that directory in a case-insensitive fashion, i.e: match a directory entry even if the name used by userspace is not a byte per byte match with the disk name, but is an equivalent case-insensitive version of the Unicode string. This operation is called a case-insensitive file name lookup. The feature is configured as an inode attribute applied to directories and inherited by its children. This attribute can only be enabled on empty directories for filesystems that support the encoding feature, thus preventing collision of file names that only differ by case. * dcache handling: For a +F directory, F2Fs only stores the first equivalent name dentry used in the dcache. This is done to prevent unintentional duplication of dentries in the dcache, while also allowing the VFS code to quickly find the right entry in the cache despite which equivalent string was used in a previous lookup, without having to resort to ->lookup(). d_hash() of casefolded directories is implemented as the hash of the casefolded string, such that we always have a well-known bucket for all the equivalencies of the same string. d_compare() uses the utf8_strncasecmp() infrastructure, which handles the comparison of equivalent, same case, names as well. For now, negative lookups are not inserted in the dcache, since they would need to be invalidated anyway, because we can't trust missing file dentries. This is bad for performance but requires some leveraging of the vfs layer to fix. We can live without that for now, and so does everyone else. * on-disk data: Despite using a specific version of the name as the internal representation within the dcache, the name stored and fetched from the disk is a byte-per-byte match with what the user requested, making this implementation 'name-preserving'. i.e. no actual information is lost when writing to storage. DX is supported by modifying the hashes used in +F directories to make them case/encoding-aware. The new disk hashes are calculated as the hash of the full casefolded string, instead of the string directly. This allows us to efficiently search for file names in the htree without requiring the user to provide an exact name. * Dealing with invalid sequences: By default, when a invalid UTF-8 sequence is identified, ext4 will treat it as an opaque byte sequence, ignoring the encoding and reverting to the old behavior for that unique file. This means that case-insensitive file name lookup will not work only for that file. An optional bit can be set in the superblock telling the filesystem code and userspace tools to enforce the encoding. When that optional bit is set, any attempt to create a file name using an invalid UTF-8 sequence will fail and return an error to userspace. * Normalization algorithm: The UTF-8 algorithms used to compare strings in f2fs is implemented in fs/unicode, and is based on a previous version developed by SGI. It implements the Canonical decomposition (NFD) algorithm described by the Unicode specification 12.1, or higher, combined with the elimination of ignorable code points (NFDi) and full case-folding (CF) as documented in fs/unicode/utf8_norm.c. NFD seems to be the best normalization method for F2FS because: - It has a lower cost than NFC/NFKC (which requires decomposing to NFD as an intermediary step) - It doesn't eliminate important semantic meaning like compatibility decompositions. Although: - This implementation is not completely linguistic accurate, because different languages have conflicting rules, which would require the specialization of the filesystem to a given locale, which brings all sorts of problems for removable media and for users who use more than one language. """ Signed-off-by: Daniel Rosenberg Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: use generic EFSBADCRC/EFSCORRUPTED

2019-07-02T22:40:41+00:00

f2fs uses EFAULT as error number to indicate filesystem is corrupted all the time, but generic filesystems use EUCLEAN for such condition, we need to change to follow others. This patch adds two new macros as below to wrap more generic error code macros, and spread them in code. EFSBADCRC EBADMSG /* Bad CRC detected */ EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */ Reported-by: Pavel Machek Signed-off-by: Chao Yu Acked-by: Pavel Machek Signed-off-by: Jaegeuk Kim

f2fs: introduce f2fs_ macros to wrap f2fs_printk()

2019-07-02T22:40:40+00:00

- Add and use f2fs_ macros - Convert f2fs_msg to f2fs_printk - Remove level from f2fs_printk and embed the level in the format - Coalesce formats and align multi-line arguments - Remove unnecessary duplicate extern f2fs_msg f2fs.h Signed-off-by: Joe Perches Signed-off-by: Chao Yu Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: fix sparse warning

2019-05-30T16:48:45+00:00

make C=2 CHECKFLAGS="-D__CHECK_ENDIAN__" CHECK dir.c dir.c:842:50: warning: cast from restricted __le32 CHECK node.c node.c:2759:40: warning: restricted __le32 degrades to integer Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim