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cifs: Grab a reference for the dentry of the cached directory during the lifetime of the cache

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We need to hold both a reference for the root/superblock as well as the directory that we
are caching. We need to drop these references before we call kill_anon_sb().

At this point, the root and the cached dentries are always the same but this will change
once we start caching other directories as well.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Ronnie Sahlberg 2021-03-09 09:07:31 +10:00 committed by Steve French
parent 269f67e1ff
commit 5e9c89d43f
3 changed files with 27 additions and 0 deletions
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17
fs/cifs/cifsfs.c
View File

@ -257,11 +257,28 @@ out_no_root:
static void cifs_kill_sb(struct super_block *sb) static void cifs_kill_sb(struct super_block *sb)
{ {
struct cifs_sb_info *cifs_sb = CIFS_SB(sb); struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
struct cifs_tcon *tcon;
struct cached_fid *cfid;
/*
* We ned to release all dentries for the cached directories
* before we kill the sb.
*/
if (cifs_sb->root) { if (cifs_sb->root) {
dput(cifs_sb->root); dput(cifs_sb->root);
cifs_sb->root = NULL; cifs_sb->root = NULL;
} }
tcon = cifs_sb_master_tcon(cifs_sb);
if (tcon) {
cfid = &tcon->crfid;
mutex_lock(&cfid->fid_mutex);
if (cfid->dentry) {
dput(cfid->dentry);
cfid->dentry = NULL;
}
mutex_unlock(&cfid->fid_mutex);
}
kill_anon_super(sb); kill_anon_super(sb);
cifs_umount(cifs_sb); cifs_umount(cifs_sb);

1
fs/cifs/cifsglob.h
View File

@ -992,6 +992,7 @@ struct cached_fid {
struct cifs_fid *fid; struct cifs_fid *fid;
struct mutex fid_mutex; struct mutex fid_mutex;
struct cifs_tcon *tcon; struct cifs_tcon *tcon;
struct dentry *dentry;
struct work_struct lease_break; struct work_struct lease_break;
struct smb2_file_all_info file_all_info; struct smb2_file_all_info file_all_info;
}; };

9
fs/cifs/smb2ops.c
View File

@ -690,6 +690,10 @@ smb2_close_cached_fid(struct kref *ref)
cfid->is_valid = false; cfid->is_valid = false;
cfid->file_all_info_is_valid = false; cfid->file_all_info_is_valid = false;
cfid->has_lease = false; cfid->has_lease = false;
if (cfid->dentry) {
dput(cfid->dentry);
cfid->dentry = NULL;
}
} }
} }
@ -747,6 +751,7 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
__le16 utf16_path = 0; /* Null - since an open of top of share */ __le16 utf16_path = 0; /* Null - since an open of top of share */
u8 oplock = SMB2_OPLOCK_LEVEL_II; u8 oplock = SMB2_OPLOCK_LEVEL_II;
struct cifs_fid *pfid; struct cifs_fid *pfid;
struct dentry *dentry;
if (tcon->nohandlecache) if (tcon->nohandlecache)
return -ENOTSUPP; return -ENOTSUPP;
@ -757,6 +762,8 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
if (strlen(path)) if (strlen(path))
return -ENOENT; return -ENOENT;
dentry = cifs_sb->root;
mutex_lock(&tcon->crfid.fid_mutex); mutex_lock(&tcon->crfid.fid_mutex);
if (tcon->crfid.is_valid) { if (tcon->crfid.is_valid) {
cifs_dbg(FYI, "found a cached root file handle\n"); cifs_dbg(FYI, "found a cached root file handle\n");
@ -881,6 +888,8 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
memcpy(tcon->crfid.fid, pfid, sizeof(struct cifs_fid)); memcpy(tcon->crfid.fid, pfid, sizeof(struct cifs_fid));
tcon->crfid.tcon = tcon; tcon->crfid.tcon = tcon;
tcon->crfid.is_valid = true; tcon->crfid.is_valid = true;
tcon->crfid.dentry = dentry;
dget(dentry);
kref_init(&tcon->crfid.refcount); kref_init(&tcon->crfid.refcount);
/* BB TBD check to see if oplock level check can be removed below */ /* BB TBD check to see if oplock level check can be removed below */