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Diffstat (limited to 'fs/afs/dir.c')
-rw-r--r--fs/afs/dir.c146
1 files changed, 128 insertions, 18 deletions
diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index e640d67274be..cc12772d0a4d 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -440,7 +440,7 @@ static int afs_dir_iterate_block(struct afs_vnode *dvnode,
* iterate through the data blob that lists the contents of an AFS directory
*/
static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
- struct key *key)
+ struct key *key, afs_dataversion_t *_dir_version)
{
struct afs_vnode *dvnode = AFS_FS_I(dir);
struct afs_xdr_dir_page *dbuf;
@@ -460,6 +460,7 @@ static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
req = afs_read_dir(dvnode, key);
if (IS_ERR(req))
return PTR_ERR(req);
+ *_dir_version = req->data_version;
/* round the file position up to the next entry boundary */
ctx->pos += sizeof(union afs_xdr_dirent) - 1;
@@ -514,7 +515,10 @@ out:
*/
static int afs_readdir(struct file *file, struct dir_context *ctx)
{
- return afs_dir_iterate(file_inode(file), ctx, afs_file_key(file));
+ afs_dataversion_t dir_version;
+
+ return afs_dir_iterate(file_inode(file), ctx, afs_file_key(file),
+ &dir_version);
}
/*
@@ -555,7 +559,8 @@ static int afs_lookup_one_filldir(struct dir_context *ctx, const char *name,
* - just returns the FID the dentry name maps to if found
*/
static int afs_do_lookup_one(struct inode *dir, struct dentry *dentry,
- struct afs_fid *fid, struct key *key)
+ struct afs_fid *fid, struct key *key,
+ afs_dataversion_t *_dir_version)
{
struct afs_super_info *as = dir->i_sb->s_fs_info;
struct afs_lookup_one_cookie cookie = {
@@ -568,7 +573,7 @@ static int afs_do_lookup_one(struct inode *dir, struct dentry *dentry,
_enter("{%lu},%p{%pd},", dir->i_ino, dentry, dentry);
/* search the directory */
- ret = afs_dir_iterate(dir, &cookie.ctx, key);
+ ret = afs_dir_iterate(dir, &cookie.ctx, key, _dir_version);
if (ret < 0) {
_leave(" = %d [iter]", ret);
return ret;
@@ -642,6 +647,7 @@ static struct inode *afs_do_lookup(struct inode *dir, struct dentry *dentry,
struct afs_server *server;
struct afs_vnode *dvnode = AFS_FS_I(dir), *vnode;
struct inode *inode = NULL, *ti;
+ afs_dataversion_t data_version = READ_ONCE(dvnode->status.data_version);
int ret, i;
_enter("{%lu},%p{%pd},", dir->i_ino, dentry, dentry);
@@ -669,12 +675,14 @@ static struct inode *afs_do_lookup(struct inode *dir, struct dentry *dentry,
cookie->fids[i].vid = as->volume->vid;
/* search the directory */
- ret = afs_dir_iterate(dir, &cookie->ctx, key);
+ ret = afs_dir_iterate(dir, &cookie->ctx, key, &data_version);
if (ret < 0) {
inode = ERR_PTR(ret);
goto out;
}
+ dentry->d_fsdata = (void *)(unsigned long)data_version;
+
inode = ERR_PTR(-ENOENT);
if (!cookie->found)
goto out;
@@ -951,12 +959,65 @@ static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
inode ? AFS_FS_I(inode) : NULL);
} else {
trace_afs_lookup(dvnode, &dentry->d_name,
- inode ? AFS_FS_I(inode) : NULL);
+ IS_ERR_OR_NULL(inode) ? NULL
+ : AFS_FS_I(inode));
}
return d;
}
/*
+ * Check the validity of a dentry under RCU conditions.
+ */
+static int afs_d_revalidate_rcu(struct dentry *dentry)
+{
+ struct afs_vnode *dvnode, *vnode;
+ struct dentry *parent;
+ struct inode *dir, *inode;
+ long dir_version, de_version;
+
+ _enter("%p", dentry);
+
+ /* Check the parent directory is still valid first. */
+ parent = READ_ONCE(dentry->d_parent);
+ dir = d_inode_rcu(parent);
+ if (!dir)
+ return -ECHILD;
+ dvnode = AFS_FS_I(dir);
+ if (test_bit(AFS_VNODE_DELETED, &dvnode->flags))
+ return -ECHILD;
+
+ if (!afs_check_validity(dvnode))
+ return -ECHILD;
+
+ /* We only need to invalidate a dentry if the server's copy changed
+ * behind our back. If we made the change, it's no problem. Note that
+ * on a 32-bit system, we only have 32 bits in the dentry to store the
+ * version.
+ */
+ dir_version = (long)READ_ONCE(dvnode->status.data_version);
+ de_version = (long)READ_ONCE(dentry->d_fsdata);
+ if (de_version != dir_version) {
+ dir_version = (long)READ_ONCE(dvnode->invalid_before);
+ if (de_version - dir_version < 0)
+ return -ECHILD;
+ }
+
+ /* Check to see if the vnode referred to by the dentry still
+ * has a callback.
+ */
+ if (d_really_is_positive(dentry)) {
+ inode = d_inode_rcu(dentry);
+ if (inode) {
+ vnode = AFS_FS_I(inode);
+ if (!afs_check_validity(vnode))
+ return -ECHILD;
+ }
+ }
+
+ return 1; /* Still valid */
+}
+
+/*
* check that a dentry lookup hit has found a valid entry
* - NOTE! the hit can be a negative hit too, so we can't assume we have an
* inode
@@ -968,11 +1029,12 @@ static int afs_d_revalidate(struct dentry *dentry, unsigned int flags)
struct dentry *parent;
struct inode *inode;
struct key *key;
- long dir_version, de_version;
+ afs_dataversion_t dir_version;
+ long de_version;
int ret;
if (flags & LOOKUP_RCU)
- return -ECHILD;
+ return afs_d_revalidate_rcu(dentry);
if (d_really_is_positive(dentry)) {
vnode = AFS_FS_I(d_inode(dentry));
@@ -1014,20 +1076,20 @@ static int afs_d_revalidate(struct dentry *dentry, unsigned int flags)
* on a 32-bit system, we only have 32 bits in the dentry to store the
* version.
*/
- dir_version = (long)dir->status.data_version;
+ dir_version = dir->status.data_version;
de_version = (long)dentry->d_fsdata;
- if (de_version == dir_version)
- goto out_valid;
+ if (de_version == (long)dir_version)
+ goto out_valid_noupdate;
- dir_version = (long)dir->invalid_before;
- if (de_version - dir_version >= 0)
+ dir_version = dir->invalid_before;
+ if (de_version - (long)dir_version >= 0)
goto out_valid;
_debug("dir modified");
afs_stat_v(dir, n_reval);
/* search the directory for this vnode */
- ret = afs_do_lookup_one(&dir->vfs_inode, dentry, &fid, key);
+ ret = afs_do_lookup_one(&dir->vfs_inode, dentry, &fid, key, &dir_version);
switch (ret) {
case 0:
/* the filename maps to something */
@@ -1080,7 +1142,8 @@ static int afs_d_revalidate(struct dentry *dentry, unsigned int flags)
}
out_valid:
- dentry->d_fsdata = (void *)dir_version;
+ dentry->d_fsdata = (void *)(unsigned long)dir_version;
+out_valid_noupdate:
dput(parent);
key_put(key);
_leave(" = 1 [valid]");
@@ -1186,6 +1249,20 @@ static void afs_prep_for_new_inode(struct afs_fs_cursor *fc,
}
/*
+ * Note that a dentry got changed. We need to set d_fsdata to the data version
+ * number derived from the result of the operation. It doesn't matter if
+ * d_fsdata goes backwards as we'll just revalidate.
+ */
+static void afs_update_dentry_version(struct afs_fs_cursor *fc,
+ struct dentry *dentry,
+ struct afs_status_cb *scb)
+{
+ if (fc->ac.error == 0)
+ dentry->d_fsdata =
+ (void *)(unsigned long)scb->status.data_version;
+}
+
+/*
* create a directory on an AFS filesystem
*/
static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
@@ -1227,6 +1304,7 @@ static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
afs_check_for_remote_deletion(&fc, dvnode);
afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
&data_version, &scb[0]);
+ afs_update_dentry_version(&fc, dentry, &scb[0]);
afs_vnode_new_inode(&fc, dentry, &iget_data, &scb[1]);
ret = afs_end_vnode_operation(&fc);
if (ret < 0)
@@ -1319,6 +1397,7 @@ static int afs_rmdir(struct inode *dir, struct dentry *dentry)
afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
&data_version, scb);
+ afs_update_dentry_version(&fc, dentry, scb);
ret = afs_end_vnode_operation(&fc);
if (ret == 0) {
afs_dir_remove_subdir(dentry);
@@ -1458,6 +1537,7 @@ static int afs_unlink(struct inode *dir, struct dentry *dentry)
&data_version, &scb[0]);
afs_vnode_commit_status(&fc, vnode, fc.cb_break_2,
&data_version_2, &scb[1]);
+ afs_update_dentry_version(&fc, dentry, &scb[0]);
ret = afs_end_vnode_operation(&fc);
if (ret == 0 && !(scb[1].have_status || scb[1].have_error))
ret = afs_dir_remove_link(dvnode, dentry, key);
@@ -1526,6 +1606,7 @@ static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
afs_check_for_remote_deletion(&fc, dvnode);
afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
&data_version, &scb[0]);
+ afs_update_dentry_version(&fc, dentry, &scb[0]);
afs_vnode_new_inode(&fc, dentry, &iget_data, &scb[1]);
ret = afs_end_vnode_operation(&fc);
if (ret < 0)
@@ -1607,6 +1688,7 @@ static int afs_link(struct dentry *from, struct inode *dir,
afs_vnode_commit_status(&fc, vnode, fc.cb_break_2,
NULL, &scb[1]);
ihold(&vnode->vfs_inode);
+ afs_update_dentry_version(&fc, dentry, &scb[0]);
d_instantiate(dentry, &vnode->vfs_inode);
mutex_unlock(&vnode->io_lock);
@@ -1686,6 +1768,7 @@ static int afs_symlink(struct inode *dir, struct dentry *dentry,
afs_check_for_remote_deletion(&fc, dvnode);
afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
&data_version, &scb[0]);
+ afs_update_dentry_version(&fc, dentry, &scb[0]);
afs_vnode_new_inode(&fc, dentry, &iget_data, &scb[1]);
ret = afs_end_vnode_operation(&fc);
if (ret < 0)
@@ -1791,6 +1874,17 @@ static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
}
}
+ /* This bit is potentially nasty as there's a potential race with
+ * afs_d_revalidate{,_rcu}(). We have to change d_fsdata on the dentry
+ * to reflect it's new parent's new data_version after the op, but
+ * d_revalidate may see old_dentry between the op having taken place
+ * and the version being updated.
+ *
+ * So drop the old_dentry for now to make other threads go through
+ * lookup instead - which we hold a lock against.
+ */
+ d_drop(old_dentry);
+
ret = -ERESTARTSYS;
if (afs_begin_vnode_operation(&fc, orig_dvnode, key, true)) {
afs_dataversion_t orig_data_version;
@@ -1802,9 +1896,9 @@ static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
if (orig_dvnode != new_dvnode) {
if (mutex_lock_interruptible_nested(&new_dvnode->io_lock, 1) < 0) {
afs_end_vnode_operation(&fc);
- goto error_rehash;
+ goto error_rehash_old;
}
- new_data_version = new_dvnode->status.data_version;
+ new_data_version = new_dvnode->status.data_version + 1;
} else {
new_data_version = orig_data_version;
new_scb = &scb[0];
@@ -1827,7 +1921,7 @@ static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
}
ret = afs_end_vnode_operation(&fc);
if (ret < 0)
- goto error_rehash;
+ goto error_rehash_old;
}
if (ret == 0) {
@@ -1853,10 +1947,26 @@ static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
drop_nlink(new_inode);
spin_unlock(&new_inode->i_lock);
}
+
+ /* Now we can update d_fsdata on the dentries to reflect their
+ * new parent's data_version.
+ *
+ * Note that if we ever implement RENAME_EXCHANGE, we'll have
+ * to update both dentries with opposing dir versions.
+ */
+ if (new_dvnode != orig_dvnode) {
+ afs_update_dentry_version(&fc, old_dentry, &scb[1]);
+ afs_update_dentry_version(&fc, new_dentry, &scb[1]);
+ } else {
+ afs_update_dentry_version(&fc, old_dentry, &scb[0]);
+ afs_update_dentry_version(&fc, new_dentry, &scb[0]);
+ }
d_move(old_dentry, new_dentry);
goto error_tmp;
}
+error_rehash_old:
+ d_rehash(new_dentry);
error_rehash:
if (rehash)
d_rehash(rehash);
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