diff options
| -rw-r--r-- | fs/locks.c | 14 | ||||
| -rw-r--r-- | include/linux/filelock.h | 15 | ||||
| -rw-r--r-- | include/linux/fs.h | 1 |
3 files changed, 24 insertions, 6 deletions
diff --git a/fs/locks.c b/fs/locks.c index 9f565802a88c..7a63fa3ca9b4 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -178,7 +178,6 @@ locks_get_lock_context(struct inode *inode, int type) { struct file_lock_context *ctx; - /* paired with cmpxchg() below */ ctx = locks_inode_context(inode); if (likely(ctx) || type == F_UNLCK) goto out; @@ -196,7 +195,18 @@ locks_get_lock_context(struct inode *inode, int type) * Assign the pointer if it's not already assigned. If it is, then * free the context we just allocated. */ - if (cmpxchg(&inode->i_flctx, NULL, ctx)) { + spin_lock(&inode->i_lock); + if (!(inode->i_opflags & IOP_FLCTX)) { + VFS_BUG_ON_INODE(inode->i_flctx, inode); + WRITE_ONCE(inode->i_flctx, ctx); + /* + * Paired with locks_inode_context(). + */ + smp_store_release(&inode->i_opflags, inode->i_opflags | IOP_FLCTX); + spin_unlock(&inode->i_lock); + } else { + VFS_BUG_ON_INODE(!inode->i_flctx, inode); + spin_unlock(&inode->i_lock); kmem_cache_free(flctx_cache, ctx); ctx = locks_inode_context(inode); } diff --git a/include/linux/filelock.h b/include/linux/filelock.h index dc15f5427680..4a8912b9653e 100644 --- a/include/linux/filelock.h +++ b/include/linux/filelock.h @@ -242,8 +242,12 @@ static inline struct file_lock_context * locks_inode_context(const struct inode *inode) { /* - * Paired with the fence in locks_get_lock_context(). + * Paired with smp_store_release in locks_get_lock_context(). + * + * Ensures ->i_flctx will be visible if we spotted the flag. */ + if (likely(!(smp_load_acquire(&inode->i_opflags) & IOP_FLCTX))) + return NULL; return READ_ONCE(inode->i_flctx); } @@ -471,7 +475,7 @@ static inline int break_lease(struct inode *inode, unsigned int mode) * could end up racing with tasks trying to set a new lease on this * file. */ - flctx = READ_ONCE(inode->i_flctx); + flctx = locks_inode_context(inode); if (!flctx) return 0; smp_mb(); @@ -490,7 +494,7 @@ static inline int break_deleg(struct inode *inode, unsigned int flags) * could end up racing with tasks trying to set a new lease on this * file. */ - flctx = READ_ONCE(inode->i_flctx); + flctx = locks_inode_context(inode); if (!flctx) return 0; smp_mb(); @@ -535,8 +539,11 @@ static inline int break_deleg_wait(struct delegated_inode *di) static inline int break_layout(struct inode *inode, bool wait) { + struct file_lock_context *flctx; + smp_mb(); - if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease)) { + flctx = locks_inode_context(inode); + if (flctx && !list_empty_careful(&flctx->flc_lease)) { unsigned int flags = LEASE_BREAK_LAYOUT; if (!wait) diff --git a/include/linux/fs.h b/include/linux/fs.h index 04ceeca12a0d..094b0adcb035 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -631,6 +631,7 @@ is_uncached_acl(struct posix_acl *acl) #define IOP_MGTIME 0x0020 #define IOP_CACHED_LINK 0x0040 #define IOP_FASTPERM_MAY_EXEC 0x0080 +#define IOP_FLCTX 0x0100 /* * Inode state bits. Protected by inode->i_lock |