From f7e86ab92f2198d30828a1a327ad2085e4a7ff7d Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Wed, 19 Aug 2009 18:13:00 -0400 Subject: [PATCH] SUNRPC: cache must take a reference to the cache detail's module on open() Otherwise we Oops if the module containing the cache detail is removed before all cache readers have closed the file. Signed-off-by: Trond Myklebust --- net/sunrpc/cache.c | 80 +++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 76 insertions(+), 4 deletions(-) diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c index db7720e453c3..45cdaff9b361 100644 --- a/net/sunrpc/cache.c +++ b/net/sunrpc/cache.c @@ -836,6 +836,8 @@ static int cache_open(struct inode *inode, struct file *filp, { struct cache_reader *rp = NULL; + if (!cd || !try_module_get(cd->owner)) + return -EACCES; nonseekable_open(inode, filp); if (filp->f_mode & FMODE_READ) { rp = kmalloc(sizeof(*rp), GFP_KERNEL); @@ -879,6 +881,7 @@ static int cache_release(struct inode *inode, struct file *filp, cd->last_close = get_seconds(); atomic_dec(&cd->readers); } + module_put(cd->owner); return 0; } @@ -1215,6 +1218,8 @@ static int content_open(struct inode *inode, struct file *file, { struct handle *han; + if (!cd || !try_module_get(cd->owner)) + return -EACCES; han = __seq_open_private(file, &cache_content_op, sizeof(*han)); if (han == NULL) return -ENOMEM; @@ -1223,6 +1228,29 @@ static int content_open(struct inode *inode, struct file *file, return 0; } +static int content_release(struct inode *inode, struct file *file, + struct cache_detail *cd) +{ + int ret = seq_release_private(inode, file); + module_put(cd->owner); + return ret; +} + +static int open_flush(struct inode *inode, struct file *file, + struct cache_detail *cd) +{ + if (!cd || !try_module_get(cd->owner)) + return -EACCES; + return nonseekable_open(inode, file); +} + +static int release_flush(struct inode *inode, struct file *file, + struct cache_detail *cd) +{ + module_put(cd->owner); + return 0; +} + static ssize_t read_flush(struct file *file, char __user *buf, size_t count, loff_t *ppos, struct cache_detail *cd) @@ -1331,13 +1359,34 @@ static int content_open_procfs(struct inode *inode, struct file *filp) return content_open(inode, filp, cd); } +static int content_release_procfs(struct inode *inode, struct file *filp) +{ + struct cache_detail *cd = PDE(inode)->data; + + return content_release(inode, filp, cd); +} + static const struct file_operations content_file_operations_procfs = { .open = content_open_procfs, .read = seq_read, .llseek = seq_lseek, - .release = seq_release_private, + .release = content_release_procfs, }; +static int open_flush_procfs(struct inode *inode, struct file *filp) +{ + struct cache_detail *cd = PDE(inode)->data; + + return open_flush(inode, filp, cd); +} + +static int release_flush_procfs(struct inode *inode, struct file *filp) +{ + struct cache_detail *cd = PDE(inode)->data; + + return release_flush(inode, filp, cd); +} + static ssize_t read_flush_procfs(struct file *filp, char __user *buf, size_t count, loff_t *ppos) { @@ -1356,9 +1405,10 @@ static ssize_t write_flush_procfs(struct file *filp, } static const struct file_operations cache_flush_operations_procfs = { - .open = nonseekable_open, + .open = open_flush_procfs, .read = read_flush_procfs, .write = write_flush_procfs, + .release = release_flush_procfs, }; static void remove_cache_proc_entries(struct cache_detail *cd) @@ -1503,13 +1553,34 @@ static int content_open_pipefs(struct inode *inode, struct file *filp) return content_open(inode, filp, cd); } +static int content_release_pipefs(struct inode *inode, struct file *filp) +{ + struct cache_detail *cd = RPC_I(inode)->private; + + return content_release(inode, filp, cd); +} + const struct file_operations content_file_operations_pipefs = { .open = content_open_pipefs, .read = seq_read, .llseek = seq_lseek, - .release = seq_release_private, + .release = content_release_pipefs, }; +static int open_flush_pipefs(struct inode *inode, struct file *filp) +{ + struct cache_detail *cd = RPC_I(inode)->private; + + return open_flush(inode, filp, cd); +} + +static int release_flush_pipefs(struct inode *inode, struct file *filp) +{ + struct cache_detail *cd = RPC_I(inode)->private; + + return release_flush(inode, filp, cd); +} + static ssize_t read_flush_pipefs(struct file *filp, char __user *buf, size_t count, loff_t *ppos) { @@ -1528,9 +1599,10 @@ static ssize_t write_flush_pipefs(struct file *filp, } const struct file_operations cache_flush_operations_pipefs = { - .open = nonseekable_open, + .open = open_flush_pipefs, .read = read_flush_pipefs, .write = write_flush_pipefs, + .release = release_flush_pipefs, }; int sunrpc_cache_register_pipefs(struct dentry *parent, -- 2.20.1