diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-05-21 22:22:44 (GMT) |
---|---|---|
committer | Al Viro <viro@zeniv.linux.org.uk> | 2013-06-29 08:57:36 (GMT) |
commit | da53be12bbb4fabbe2e9f6f908de0cf478b5161d (patch) | |
tree | a0436fb462a7b16c82e58336e17c55b814f7be6b /fs/dcache.c | |
parent | 642b704cd7a29be0b8900971eb525086c1c995b7 (diff) | |
download | linux-da53be12bbb4fabbe2e9f6f908de0cf478b5161d.tar.xz |
Don't pass inode to ->d_hash() and ->d_compare()
Instances either don't look at it at all (the majority of cases) or
only want it to find the superblock (which can be had as dentry->d_sb).
A few cases that want more are actually safe with dentry->d_inode -
the only precaution needed is the check that it hadn't been replaced with
NULL by rmdir() or by overwriting rename(), which case should be simply
treated as cache miss.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/dcache.c')
-rw-r--r-- | fs/dcache.c | 27 |
1 files changed, 10 insertions, 17 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index b692c7e..3199fe6 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1723,7 +1723,7 @@ EXPORT_SYMBOL(d_add_ci); * Do the slow-case of the dentry name compare. * * Unlike the dentry_cmp() function, we need to atomically - * load the name, length and inode information, so that the + * load the name and length information, so that the * filesystem can rely on them, and can use the 'name' and * 'len' information without worrying about walking off the * end of memory etc. @@ -1741,22 +1741,18 @@ enum slow_d_compare { static noinline enum slow_d_compare slow_dentry_cmp( const struct dentry *parent, - struct inode *inode, struct dentry *dentry, unsigned int seq, const struct qstr *name) { int tlen = dentry->d_name.len; const char *tname = dentry->d_name.name; - struct inode *i = dentry->d_inode; if (read_seqcount_retry(&dentry->d_seq, seq)) { cpu_relax(); return D_COMP_SEQRETRY; } - if (parent->d_op->d_compare(parent, inode, - dentry, i, - tlen, tname, name)) + if (parent->d_op->d_compare(parent, dentry, tlen, tname, name)) return D_COMP_NOMATCH; return D_COMP_OK; } @@ -1766,7 +1762,6 @@ static noinline enum slow_d_compare slow_dentry_cmp( * @parent: parent dentry * @name: qstr of name we wish to find * @seqp: returns d_seq value at the point where the dentry was found - * @inode: returns dentry->d_inode when the inode was found valid. * Returns: dentry, or NULL * * __d_lookup_rcu is the dcache lookup function for rcu-walk name @@ -1793,7 +1788,7 @@ static noinline enum slow_d_compare slow_dentry_cmp( */ struct dentry *__d_lookup_rcu(const struct dentry *parent, const struct qstr *name, - unsigned *seqp, struct inode *inode) + unsigned *seqp) { u64 hashlen = name->hash_len; const unsigned char *str = name->name; @@ -1827,11 +1822,10 @@ struct dentry *__d_lookup_rcu(const struct dentry *parent, seqretry: /* * The dentry sequence count protects us from concurrent - * renames, and thus protects inode, parent and name fields. + * renames, and thus protects parent and name fields. * * The caller must perform a seqcount check in order - * to do anything useful with the returned dentry, - * including using the 'd_inode' pointer. + * to do anything useful with the returned dentry. * * NOTE! We do a "raw" seqcount_begin here. That means that * we don't wait for the sequence count to stabilize if it @@ -1845,12 +1839,12 @@ seqretry: continue; if (d_unhashed(dentry)) continue; - *seqp = seq; if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) { if (dentry->d_name.hash != hashlen_hash(hashlen)) continue; - switch (slow_dentry_cmp(parent, inode, dentry, seq, name)) { + *seqp = seq; + switch (slow_dentry_cmp(parent, dentry, seq, name)) { case D_COMP_OK: return dentry; case D_COMP_NOMATCH: @@ -1862,6 +1856,7 @@ seqretry: if (dentry->d_name.hash_len != hashlen) continue; + *seqp = seq; if (!dentry_cmp(dentry, str, hashlen_len(hashlen))) return dentry; } @@ -1959,9 +1954,7 @@ struct dentry *__d_lookup(const struct dentry *parent, const struct qstr *name) if (parent->d_flags & DCACHE_OP_COMPARE) { int tlen = dentry->d_name.len; const char *tname = dentry->d_name.name; - if (parent->d_op->d_compare(parent, parent->d_inode, - dentry, dentry->d_inode, - tlen, tname, name)) + if (parent->d_op->d_compare(parent, dentry, tlen, tname, name)) goto next; } else { if (dentry->d_name.len != len) @@ -1998,7 +1991,7 @@ struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name) */ name->hash = full_name_hash(name->name, name->len); if (dir->d_flags & DCACHE_OP_HASH) { - int err = dir->d_op->d_hash(dir, dir->d_inode, name); + int err = dir->d_op->d_hash(dir, name); if (unlikely(err < 0)) return ERR_PTR(err); } |