diff options
Diffstat (limited to 'fs/dcache.c')
| -rw-r--r-- | fs/dcache.c | 128 |
1 files changed, 93 insertions, 35 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index a88948b8bd17..89509b5a090e 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -36,6 +36,7 @@ #include <linux/bit_spinlock.h> #include <linux/rculist_bl.h> #include <linux/prefetch.h> +#include <linux/ratelimit.h> #include "internal.h" /* @@ -225,7 +226,7 @@ static void dentry_unlink_inode(struct dentry * dentry) } /* - * dentry_lru_(add|del|move_tail) must be called with d_lock held. + * dentry_lru_(add|del|prune|move_tail) must be called with d_lock held. */ static void dentry_lru_add(struct dentry *dentry) { @@ -245,6 +246,9 @@ static void __dentry_lru_del(struct dentry *dentry) dentry_stat.nr_unused--; } +/* + * Remove a dentry with references from the LRU. + */ static void dentry_lru_del(struct dentry *dentry) { if (!list_empty(&dentry->d_lru)) { @@ -254,6 +258,23 @@ static void dentry_lru_del(struct dentry *dentry) } } +/* + * Remove a dentry that is unreferenced and about to be pruned + * (unhashed and destroyed) from the LRU, and inform the file system. + * This wrapper should be called _prior_ to unhashing a victim dentry. + */ +static void dentry_lru_prune(struct dentry *dentry) +{ + if (!list_empty(&dentry->d_lru)) { + if (dentry->d_flags & DCACHE_OP_PRUNE) + dentry->d_op->d_prune(dentry); + + spin_lock(&dcache_lru_lock); + __dentry_lru_del(dentry); + spin_unlock(&dcache_lru_lock); + } +} + static void dentry_lru_move_tail(struct dentry *dentry) { spin_lock(&dcache_lru_lock); @@ -403,8 +424,12 @@ relock: if (ref) dentry->d_count--; - /* if dentry was on the d_lru list delete it from there */ - dentry_lru_del(dentry); + /* + * if dentry was on the d_lru list delete it from there. + * inform the fs via d_prune that this dentry is about to be + * unhashed and destroyed. + */ + dentry_lru_prune(dentry); /* if it was on the hash then remove it */ __d_drop(dentry); return d_kill(dentry, parent); @@ -522,9 +547,11 @@ int d_invalidate(struct dentry * dentry) * would make it unreachable from the root, * we might still populate it if it was a * working directory or similar). + * We also need to leave mountpoints alone, + * directory or not. */ - if (dentry->d_count > 1) { - if (dentry->d_inode && S_ISDIR(dentry->d_inode->i_mode)) { + if (dentry->d_count > 1 && dentry->d_inode) { + if (S_ISDIR(dentry->d_inode->i_mode) || d_mountpoint(dentry)) { spin_unlock(&dentry->d_lock); return -EBUSY; } @@ -854,8 +881,12 @@ static void shrink_dcache_for_umount_subtree(struct dentry *dentry) do { struct inode *inode; - /* detach from the system */ - dentry_lru_del(dentry); + /* + * remove the dentry from the lru, and inform + * the fs that this dentry is about to be + * unhashed and destroyed. + */ + dentry_lru_prune(dentry); __d_shrink(dentry); if (dentry->d_count != 0) { @@ -1283,6 +1314,8 @@ void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op) dentry->d_flags |= DCACHE_OP_REVALIDATE; if (op->d_delete) dentry->d_flags |= DCACHE_OP_DELETE; + if (op->d_prune) + dentry->d_flags |= DCACHE_OP_PRUNE; } EXPORT_SYMBOL(d_set_d_op); @@ -2351,8 +2384,16 @@ struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode) actual = __d_unalias(inode, dentry, alias); } write_sequnlock(&rename_lock); - if (IS_ERR(actual)) + if (IS_ERR(actual)) { + if (PTR_ERR(actual) == -ELOOP) + pr_warn_ratelimited( + "VFS: Lookup of '%s' in %s %s" + " would have caused loop\n", + dentry->d_name.name, + inode->i_sb->s_type->name, + inode->i_sb->s_id); dput(alias); + } goto out_nolock; } } @@ -2398,16 +2439,14 @@ static int prepend_name(char **buffer, int *buflen, struct qstr *name) /** * prepend_path - Prepend path string to a buffer * @path: the dentry/vfsmount to report - * @root: root vfsmnt/dentry (may be modified by this function) + * @root: root vfsmnt/dentry * @buffer: pointer to the end of the buffer * @buflen: pointer to buffer length * * Caller holds the rename_lock. - * - * If path is not reachable from the supplied root, then the value of - * root is changed (without modifying refcounts). */ -static int prepend_path(const struct path *path, struct path *root, +static int prepend_path(const struct path *path, + const struct path *root, char **buffer, int *buflen) { struct dentry *dentry = path->dentry; @@ -2442,10 +2481,10 @@ static int prepend_path(const struct path *path, struct path *root, dentry = parent; } -out: if (!error && !slash) error = prepend(buffer, buflen, "/", 1); +out: br_read_unlock(vfsmount_lock); return error; @@ -2459,15 +2498,17 @@ global_root: WARN(1, "Root dentry has weird name <%.*s>\n", (int) dentry->d_name.len, dentry->d_name.name); } - root->mnt = vfsmnt; - root->dentry = dentry; + if (!slash) + error = prepend(buffer, buflen, "/", 1); + if (!error) + error = vfsmnt->mnt_ns ? 1 : 2; goto out; } /** * __d_path - return the path of a dentry * @path: the dentry/vfsmount to report - * @root: root vfsmnt/dentry (may be modified by this function) + * @root: root vfsmnt/dentry * @buf: buffer to return value in * @buflen: buffer length * @@ -2478,10 +2519,10 @@ global_root: * * "buflen" should be positive. * - * If path is not reachable from the supplied root, then the value of - * root is changed (without modifying refcounts). + * If the path is not reachable from the supplied root, return %NULL. */ -char *__d_path(const struct path *path, struct path *root, +char *__d_path(const struct path *path, + const struct path *root, char *buf, int buflen) { char *res = buf + buflen; @@ -2492,7 +2533,28 @@ char *__d_path(const struct path *path, struct path *root, error = prepend_path(path, root, &res, &buflen); write_sequnlock(&rename_lock); - if (error) + if (error < 0) + return ERR_PTR(error); + if (error > 0) + return NULL; + return res; +} + +char *d_absolute_path(const struct path *path, + char *buf, int buflen) +{ + struct path root = {}; + char *res = buf + buflen; + int error; + + prepend(&res, &buflen, "\0", 1); + write_seqlock(&rename_lock); + error = prepend_path(path, &root, &res, &buflen); + write_sequnlock(&rename_lock); + + if (error > 1) + error = -EINVAL; + if (error < 0) return ERR_PTR(error); return res; } @@ -2500,8 +2562,9 @@ char *__d_path(const struct path *path, struct path *root, /* * same as __d_path but appends "(deleted)" for unlinked files. */ -static int path_with_deleted(const struct path *path, struct path *root, - char **buf, int *buflen) +static int path_with_deleted(const struct path *path, + const struct path *root, + char **buf, int *buflen) { prepend(buf, buflen, "\0", 1); if (d_unlinked(path->dentry)) { @@ -2538,7 +2601,6 @@ char *d_path(const struct path *path, char *buf, int buflen) { char *res = buf + buflen; struct path root; - struct path tmp; int error; /* @@ -2553,9 +2615,8 @@ char *d_path(const struct path *path, char *buf, int buflen) get_fs_root(current->fs, &root); write_seqlock(&rename_lock); - tmp = root; - error = path_with_deleted(path, &tmp, &res, &buflen); - if (error) + error = path_with_deleted(path, &root, &res, &buflen); + if (error < 0) res = ERR_PTR(error); write_sequnlock(&rename_lock); path_put(&root); @@ -2576,7 +2637,6 @@ char *d_path_with_unreachable(const struct path *path, char *buf, int buflen) { char *res = buf + buflen; struct path root; - struct path tmp; int error; if (path->dentry->d_op && path->dentry->d_op->d_dname) @@ -2584,9 +2644,8 @@ char *d_path_with_unreachable(const struct path *path, char *buf, int buflen) get_fs_root(current->fs, &root); write_seqlock(&rename_lock); - tmp = root; - error = path_with_deleted(path, &tmp, &res, &buflen); - if (!error && !path_equal(&tmp, &root)) + error = path_with_deleted(path, &root, &res, &buflen); + if (error > 0) error = prepend_unreachable(&res, &buflen); write_sequnlock(&rename_lock); path_put(&root); @@ -2717,19 +2776,18 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) write_seqlock(&rename_lock); if (!d_unlinked(pwd.dentry)) { unsigned long len; - struct path tmp = root; char *cwd = page + PAGE_SIZE; int buflen = PAGE_SIZE; prepend(&cwd, &buflen, "\0", 1); - error = prepend_path(&pwd, &tmp, &cwd, &buflen); + error = prepend_path(&pwd, &root, &cwd, &buflen); write_sequnlock(&rename_lock); - if (error) + if (error < 0) goto out; /* Unreachable from current root */ - if (!path_equal(&tmp, &root)) { + if (error > 0) { error = prepend_unreachable(&cwd, &buflen); if (error) goto out; |