diff options
| -rw-r--r-- | Documentation/00-INDEX | 6 | ||||
| -rw-r--r-- | Documentation/filesystems/00-INDEX | 4 | ||||
| -rw-r--r-- | Documentation/filesystems/locks.txt (renamed from Documentation/locks.txt) | 10 | ||||
| -rw-r--r-- | Documentation/filesystems/mandatory-locking.txt (renamed from Documentation/mandatory.txt) | 21 | ||||
| -rw-r--r-- | fs/9p/vfs_file.c | 2 | ||||
| -rw-r--r-- | fs/afs/flock.c | 3 | ||||
| -rw-r--r-- | fs/gfs2/ops_file.c | 4 | ||||
| -rw-r--r-- | fs/locks.c | 192 | ||||
| -rw-r--r-- | fs/nfs/file.c | 3 | ||||
| -rw-r--r-- | fs/nfsd/nfs4state.c | 2 | ||||
| -rw-r--r-- | fs/nfsd/vfs.c | 13 | ||||
| -rw-r--r-- | fs/proc/proc_misc.c | 19 | ||||
| -rw-r--r-- | fs/read_write.c | 2 | ||||
| -rw-r--r-- | include/linux/fs.h | 22 |
14 files changed, 157 insertions, 146 deletions
diff --git a/Documentation/00-INDEX b/Documentation/00-INDEX index 43e89b1537d..cc10ce7dc33 100644 --- a/Documentation/00-INDEX +++ b/Documentation/00-INDEX @@ -145,7 +145,7 @@ fb/ feature-removal-schedule.txt - list of files and features that are going to be removed. filesystems/ - - directory with info on the various filesystems that Linux supports. + - info on the vfs and the various filesystems that Linux supports. firmware_class/ - request_firmware() hotplug interface info. floppy.txt @@ -230,8 +230,6 @@ local_ops.txt - semantics and behavior of local atomic operations. lockdep-design.txt - documentation on the runtime locking correctness validator. -locks.txt - - info on file locking implementations, flock() vs. fcntl(), etc. logo.gif - full colour GIF image of Linux logo (penguin - Tux). logo.txt @@ -240,8 +238,6 @@ m68k/ - directory with info about Linux on Motorola 68k architecture. magic-number.txt - list of magic numbers used to mark/protect kernel data structures. -mandatory.txt - - info on the Linux implementation of Sys V mandatory file locking. mca.txt - info on supporting Micro Channel Architecture (e.g. PS/2) systems. md.txt diff --git a/Documentation/filesystems/00-INDEX b/Documentation/filesystems/00-INDEX index 59db1bca702..599593a1706 100644 --- a/Documentation/filesystems/00-INDEX +++ b/Documentation/filesystems/00-INDEX @@ -52,6 +52,10 @@ isofs.txt - info and mount options for the ISO 9660 (CDROM) filesystem. jfs.txt - info and mount options for the JFS filesystem. +locks.txt + - info on file locking implementations, flock() vs. fcntl(), etc. +mandatory-locking.txt + - info on the Linux implementation of Sys V mandatory file locking. ncpfs.txt - info on Novell Netware(tm) filesystem using NCP protocol. ntfs.txt diff --git a/Documentation/locks.txt b/Documentation/filesystems/locks.txt index e3b402ef33b..fab857accbd 100644 --- a/Documentation/locks.txt +++ b/Documentation/filesystems/locks.txt @@ -53,11 +53,11 @@ fcntl(), with all the problems that implies. 1.3 Mandatory Locking As A Mount Option --------------------------------------- -Mandatory locking, as described in 'Documentation/mandatory.txt' was prior -to this release a general configuration option that was valid for all -mounted filesystems. This had a number of inherent dangers, not the least -of which was the ability to freeze an NFS server by asking it to read a -file for which a mandatory lock existed. +Mandatory locking, as described in 'Documentation/filesystems/mandatory.txt' +was prior to this release a general configuration option that was valid for +all mounted filesystems. This had a number of inherent dangers, not the +least of which was the ability to freeze an NFS server by asking it to read +a file for which a mandatory lock existed. From this release of the kernel, mandatory locking can be turned on and off on a per-filesystem basis, using the mount options 'mand' and 'nomand'. diff --git a/Documentation/mandatory.txt b/Documentation/filesystems/mandatory-locking.txt index bc449d49eee..0979d1d2ca8 100644 --- a/Documentation/mandatory.txt +++ b/Documentation/filesystems/mandatory-locking.txt @@ -3,7 +3,26 @@ Andy Walker <andy@lysaker.kvaerner.no> 15 April 1996 - + (Updated September 2007) + +0. Why you should avoid mandatory locking +----------------------------------------- + +The Linux implementation is prey to a number of difficult-to-fix race +conditions which in practice make it not dependable: + + - The write system call checks for a mandatory lock only once + at its start. It is therefore possible for a lock request to + be granted after this check but before the data is modified. + A process may then see file data change even while a mandatory + lock was held. + - Similarly, an exclusive lock may be granted on a file after + the kernel has decided to proceed with a read, but before the + read has actually completed, and the reading process may see + the file data in a state which should not have been visible + to it. + - Similar races make the claimed mutual exclusion between lock + and mmap similarly unreliable. 1. What is mandatory locking? ------------------------------ diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c index 2a40c2946d0..716691689fd 100644 --- a/fs/9p/vfs_file.c +++ b/fs/9p/vfs_file.c @@ -105,7 +105,7 @@ static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl) P9_DPRINTK(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl); /* No mandatory locks */ - if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID) + if (__mandatory_lock(inode)) return -ENOLCK; if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) { diff --git a/fs/afs/flock.c b/fs/afs/flock.c index af6952e39a1..210acafe4a9 100644 --- a/fs/afs/flock.c +++ b/fs/afs/flock.c @@ -524,8 +524,7 @@ int afs_lock(struct file *file, int cmd, struct file_lock *fl) (long long) fl->fl_start, (long long) fl->fl_end); /* AFS doesn't support mandatory locks */ - if ((vnode->vfs_inode.i_mode & (S_ISGID | S_IXGRP)) == S_ISGID && - fl->fl_type != F_UNLCK) + if (__mandatory_lock(&vnode->vfs_inode) && fl->fl_type != F_UNLCK) return -ENOLCK; if (IS_GETLK(cmd)) diff --git a/fs/gfs2/ops_file.c b/fs/gfs2/ops_file.c index 46a9e10ff17..7eb4b280ac6 100644 --- a/fs/gfs2/ops_file.c +++ b/fs/gfs2/ops_file.c @@ -535,7 +535,7 @@ static int gfs2_lock(struct file *file, int cmd, struct file_lock *fl) if (!(fl->fl_flags & FL_POSIX)) return -ENOLCK; - if ((ip->i_inode.i_mode & (S_ISGID | S_IXGRP)) == S_ISGID) + if (__mandatory_lock(&ip->i_inode)) return -ENOLCK; if (sdp->sd_args.ar_localflocks) { @@ -636,7 +636,7 @@ static int gfs2_flock(struct file *file, int cmd, struct file_lock *fl) if (!(fl->fl_flags & FL_FLOCK)) return -ENOLCK; - if ((ip->i_inode.i_mode & (S_ISGID | S_IXGRP)) == S_ISGID) + if (__mandatory_lock(&ip->i_inode)) return -ENOLCK; if (sdp->sd_args.ar_localflocks) diff --git a/fs/locks.c b/fs/locks.c index c795eaaf6c4..7f9a3ea4741 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -534,7 +534,9 @@ static void locks_insert_block(struct file_lock *blocker, static void locks_wake_up_blocks(struct file_lock *blocker) { while (!list_empty(&blocker->fl_block)) { - struct file_lock *waiter = list_entry(blocker->fl_block.next, + struct file_lock *waiter; + + waiter = list_first_entry(&blocker->fl_block, struct file_lock, fl_block); __locks_delete_block(waiter); if (waiter->fl_lmops && waiter->fl_lmops->fl_notify) @@ -668,7 +670,7 @@ posix_test_lock(struct file *filp, struct file_lock *fl) for (cfl = filp->f_path.dentry->d_inode->i_flock; cfl; cfl = cfl->fl_next) { if (!IS_POSIX(cfl)) continue; - if (posix_locks_conflict(cfl, fl)) + if (posix_locks_conflict(fl, cfl)) break; } if (cfl) @@ -698,13 +700,12 @@ EXPORT_SYMBOL(posix_test_lock); static int posix_locks_deadlock(struct file_lock *caller_fl, struct file_lock *block_fl) { - struct list_head *tmp; + struct file_lock *fl; next_task: if (posix_same_owner(caller_fl, block_fl)) return 1; - list_for_each(tmp, &blocked_list) { - struct file_lock *fl = list_entry(tmp, struct file_lock, fl_link); + list_for_each_entry(fl, &blocked_list, fl_link) { if (posix_same_owner(fl, block_fl)) { fl = fl->fl_next; block_fl = fl; @@ -715,8 +716,7 @@ next_task: } /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks - * at the head of the list, but that's secret knowledge known only to - * flock_lock_file and posix_lock_file. + * after any leases, but before any posix locks. * * Note that if called with an FL_EXISTS argument, the caller may determine * whether or not a lock was successfully freed by testing the return @@ -733,6 +733,15 @@ static int flock_lock_file(struct file *filp, struct file_lock *request) lock_kernel(); if (request->fl_flags & FL_ACCESS) goto find_conflict; + + if (request->fl_type != F_UNLCK) { + error = -ENOMEM; + new_fl = locks_alloc_lock(); + if (new_fl == NULL) + goto out; + error = 0; + } + for_each_lock(inode, before) { struct file_lock *fl = *before; if (IS_POSIX(fl)) @@ -754,10 +763,6 @@ static int flock_lock_file(struct file *filp, struct file_lock *request) goto out; } - error = -ENOMEM; - new_fl = locks_alloc_lock(); - if (new_fl == NULL) - goto out; /* * If a higher-priority process was blocked on the old file lock, * give it the opportunity to lock the file. @@ -819,7 +824,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str lock_kernel(); if (request->fl_type != F_UNLCK) { for_each_lock(inode, before) { - struct file_lock *fl = *before; + fl = *before; if (!IS_POSIX(fl)) continue; if (!posix_locks_conflict(request, fl)) @@ -1113,7 +1118,7 @@ int locks_mandatory_area(int read_write, struct inode *inode, * If we've been sleeping someone might have * changed the permissions behind our back. */ - if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID) + if (__mandatory_lock(inode)) continue; } @@ -1337,6 +1342,7 @@ int fcntl_getlease(struct file *filp) int generic_setlease(struct file *filp, long arg, struct file_lock **flp) { struct file_lock *fl, **before, **my_before = NULL, *lease; + struct file_lock *new_fl = NULL; struct dentry *dentry = filp->f_path.dentry; struct inode *inode = dentry->d_inode; int error, rdlease_count = 0, wrlease_count = 0; @@ -1363,6 +1369,11 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp) || (atomic_read(&inode->i_count) > 1))) goto out; + error = -ENOMEM; + new_fl = locks_alloc_lock(); + if (new_fl == NULL) + goto out; + /* * At this point, we know that if there is an exclusive * lease on this file, then we hold it on this filp @@ -1405,18 +1416,15 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp) if (!leases_enable) goto out; - error = -ENOMEM; - fl = locks_alloc_lock(); - if (fl == NULL) - goto out; - - locks_copy_lock(fl, lease); + locks_copy_lock(new_fl, lease); + locks_insert_lock(before, new_fl); - locks_insert_lock(before, fl); + *flp = new_fl; + return 0; - *flp = fl; - error = 0; out: + if (new_fl != NULL) + locks_free_lock(new_fl); return error; } EXPORT_SYMBOL(generic_setlease); @@ -1752,9 +1760,7 @@ int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd, /* Don't allow mandatory locks on files that may be memory mapped * and shared. */ - if (IS_MANDLOCK(inode) && - (inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID && - mapping_writably_mapped(filp->f_mapping)) { + if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) { error = -EAGAIN; goto out; } @@ -1878,9 +1884,7 @@ int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd, /* Don't allow mandatory locks on files that may be memory mapped * and shared. */ - if (IS_MANDLOCK(inode) && - (inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID && - mapping_writably_mapped(filp->f_mapping)) { + if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) { error = -EAGAIN; goto out; } @@ -2062,138 +2066,114 @@ int vfs_cancel_lock(struct file *filp, struct file_lock *fl) EXPORT_SYMBOL_GPL(vfs_cancel_lock); -static void lock_get_status(char* out, struct file_lock *fl, int id, char *pfx) +#ifdef CONFIG_PROC_FS +#include <linux/seq_file.h> + +static void lock_get_status(struct seq_file *f, struct file_lock *fl, + int id, char *pfx) { struct inode *inode = NULL; if (fl->fl_file != NULL) inode = fl->fl_file->f_path.dentry->d_inode; - out += sprintf(out, "%d:%s ", id, pfx); + seq_printf(f, "%d:%s ", id, pfx); if (IS_POSIX(fl)) { - out += sprintf(out, "%6s %s ", + seq_printf(f, "%6s %s ", (fl->fl_flags & FL_ACCESS) ? "ACCESS" : "POSIX ", (inode == NULL) ? "*NOINODE*" : - (IS_MANDLOCK(inode) && - (inode->i_mode & (S_IXGRP | S_ISGID)) == S_ISGID) ? - "MANDATORY" : "ADVISORY "); + mandatory_lock(inode) ? "MANDATORY" : "ADVISORY "); } else if (IS_FLOCK(fl)) { if (fl->fl_type & LOCK_MAND) { - out += sprintf(out, "FLOCK MSNFS "); + seq_printf(f, "FLOCK MSNFS "); } else { - out += sprintf(out, "FLOCK ADVISORY "); + seq_printf(f, "FLOCK ADVISORY "); } } else if (IS_LEASE(fl)) { - out += sprintf(out, "LEASE "); + seq_printf(f, "LEASE "); if (fl->fl_type & F_INPROGRESS) - out += sprintf(out, "BREAKING "); + seq_printf(f, "BREAKING "); else if (fl->fl_file) - out += sprintf(out, "ACTIVE "); + seq_printf(f, "ACTIVE "); else - out += sprintf(out, "BREAKER "); + seq_printf(f, "BREAKER "); } else { - out += sprintf(out, "UNKNOWN UNKNOWN "); + seq_printf(f, "UNKNOWN UNKNOWN "); } if (fl->fl_type & LOCK_MAND) { - out += sprintf(out, "%s ", + seq_printf(f, "%s ", (fl->fl_type & LOCK_READ) ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ " : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE "); } else { - out += sprintf(out, "%s ", + seq_printf(f, "%s ", (fl->fl_type & F_INPROGRESS) ? (fl->fl_type & F_UNLCK) ? "UNLCK" : "READ " : (fl->fl_type & F_WRLCK) ? "WRITE" : "READ "); } if (inode) { #ifdef WE_CAN_BREAK_LSLK_NOW - out += sprintf(out, "%d %s:%ld ", fl->fl_pid, + seq_printf(f, "%d %s:%ld ", fl->fl_pid, inode->i_sb->s_id, inode->i_ino); #else /* userspace relies on this representation of dev_t ;-( */ - out += sprintf(out, "%d %02x:%02x:%ld ", fl->fl_pid, + seq_printf(f, "%d %02x:%02x:%ld ", fl->fl_pid, MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev), inode->i_ino); #endif } else { - out += sprintf(out, "%d <none>:0 ", fl->fl_pid); + seq_printf(f, "%d <none>:0 ", fl->fl_pid); } if (IS_POSIX(fl)) { if (fl->fl_end == OFFSET_MAX) - out += sprintf(out, "%Ld EOF\n", fl->fl_start); + seq_printf(f, "%Ld EOF\n", fl->fl_start); else - out += sprintf(out, "%Ld %Ld\n", fl->fl_start, - fl->fl_end); + seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end); } else { - out += sprintf(out, "0 EOF\n"); + seq_printf(f, "0 EOF\n"); } } -static void move_lock_status(char **p, off_t* pos, off_t offset) +static int locks_show(struct seq_file *f, void *v) { - int len; - len = strlen(*p); - if(*pos >= offset) { - /* the complete line is valid */ - *p += len; - *pos += len; - return; - } - if(*pos+len > offset) { - /* use the second part of the line */ - int i = offset-*pos; - memmove(*p,*p+i,len-i); - *p += len-i; - *pos += len; - return; - } - /* discard the complete line */ - *pos += len; + struct file_lock *fl, *bfl; + + fl = list_entry(v, struct file_lock, fl_link); + + lock_get_status(f, fl, (long)f->private, ""); + + list_for_each_entry(bfl, &fl->fl_block, fl_block) + lock_get_status(f, bfl, (long)f->private, " ->"); + + f->private++; + return 0; } -/** - * get_locks_status - reports lock usage in /proc/locks - * @buffer: address in userspace to write into - * @start: ? - * @offset: how far we are through the buffer - * @length: how much to read - */ +static void *locks_start(struct seq_file *f, loff_t *pos) +{ + lock_kernel(); + f->private = (void *)1; + return seq_list_start(&file_lock_list, *pos); +} -int get_locks_status(char *buffer, char **start, off_t offset, int length) +static void *locks_next(struct seq_file *f, void *v, loff_t *pos) { - struct list_head *tmp; - char *q = buffer; - off_t pos = 0; - int i = 0; + return seq_list_next(v, &file_lock_list, pos); +} - lock_kernel(); - list_for_each(tmp, &file_lock_list) { - struct list_head *btmp; - struct file_lock *fl = list_entry(tmp, struct file_lock, fl_link); - lock_get_status(q, fl, ++i, ""); - move_lock_status(&q, &pos, offset); - - if(pos >= offset+length) - goto done; - - list_for_each(btmp, &fl->fl_block) { - struct file_lock *bfl = list_entry(btmp, - struct file_lock, fl_block); - lock_get_status(q, bfl, i, " ->"); - move_lock_status(&q, &pos, offset); - - if(pos >= offset+length) - goto done; - } - } -done: +static void locks_stop(struct seq_file *f, void *v) +{ unlock_kernel(); - *start = buffer; - if(q-buffer < length) - return (q-buffer); - return length; } +struct seq_operations locks_seq_operations = { + .start = locks_start, + .next = locks_next, + .stop = locks_stop, + .show = locks_show, +}; +#endif + /** * lock_may_read - checks that the region is free of locks * @inode: the inode that is being read diff --git a/fs/nfs/file.c b/fs/nfs/file.c index c664bb92142..08c7c7387fc 100644 --- a/fs/nfs/file.c +++ b/fs/nfs/file.c @@ -577,8 +577,7 @@ static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl) nfs_inc_stats(inode, NFSIOS_VFSLOCK); /* No mandatory locks over NFS */ - if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID && - fl->fl_type != F_UNLCK) + if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK) return -ENOLCK; if (IS_GETLK(cmd)) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 6f182d25793..31673cd251c 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -2035,7 +2035,7 @@ static inline int io_during_grace_disallowed(struct inode *inode, int flags) { return nfs4_in_grace() && (flags & (RD_STATE | WR_STATE)) - && MANDATORY_LOCK(inode); + && mandatory_lock(inode); } /* diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index cec78c82b1f..2a8d665b134 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -61,12 +61,6 @@ #define NFSDDBG_FACILITY NFSDDBG_FILEOP -/* We must ignore files (but only files) which might have mandatory - * locks on them because there is no way to know if the accesser has - * the lock. - */ -#define IS_ISMNDLK(i) (S_ISREG((i)->i_mode) && MANDATORY_LOCK(i)) - /* * This is a cache of readahead params that help us choose the proper * readahead strategy. Initially, we set all readahead parameters to 0 @@ -689,7 +683,12 @@ nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, err = nfserr_perm; if (IS_APPEND(inode) && (access & MAY_WRITE)) goto out; - if (IS_ISMNDLK(inode)) + /* + * We must ignore files (but only files) which might have mandatory + * locks on them because there is no way to know if the accesser has + * the lock. + */ + if (S_ISREG((inode)->i_mode) && mandatory_lock(inode)) goto out; if (!inode->i_fop) diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c index b872a01ad3a..0071939c009 100644 --- a/fs/proc/proc_misc.c +++ b/fs/proc/proc_misc.c @@ -66,7 +66,6 @@ extern int get_stram_list(char *); extern int get_filesystem_list(char *); extern int get_exec_domain_list(char *); extern int get_dma_list(char *); -extern int get_locks_status (char *, char **, off_t, int); static int proc_calc_metrics(char *page, char **start, off_t off, int count, int *eof, int len) @@ -624,16 +623,18 @@ static int cmdline_read_proc(char *page, char **start, off_t off, return proc_calc_metrics(page, start, off, count, eof, len); } -static int locks_read_proc(char *page, char **start, off_t off, - int count, int *eof, void *data) +static int locks_open(struct inode *inode, struct file *filp) { - int len = get_locks_status(page, start, off, count); - - if (len < count) - *eof = 1; - return len; + return seq_open(filp, &locks_seq_operations); } +static const struct file_operations proc_locks_operations = { + .open = locks_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + static int execdomains_read_proc(char *page, char **start, off_t off, int count, int *eof, void *data) { @@ -691,7 +692,6 @@ void __init proc_misc_init(void) #endif {"filesystems", filesystems_read_proc}, {"cmdline", cmdline_read_proc}, - {"locks", locks_read_proc}, {"execdomains", execdomains_read_proc}, {NULL,} }; @@ -709,6 +709,7 @@ void __init proc_misc_init(void) entry->proc_fops = &proc_kmsg_operations; } #endif + create_seq_entry("locks", 0, &proc_locks_operations); create_seq_entry("devices", 0, &proc_devinfo_operations); create_seq_entry("cpuinfo", 0, &proc_cpuinfo_operations); #ifdef CONFIG_BLOCK diff --git a/fs/read_write.c b/fs/read_write.c index 507ddff48a9..124693e8d3f 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -205,7 +205,7 @@ int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count if (unlikely((pos < 0) || (loff_t) (pos + count) < 0)) goto Einval; - if (unlikely(inode->i_flock && MANDATORY_LOCK(inode))) { + if (unlikely(inode->i_flock && mandatory_lock(inode))) { int retval = locks_mandatory_area( read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE, inode, file, pos, count); diff --git a/include/linux/fs.h b/include/linux/fs.h index 6d760f1ad87..4a6a21077ba 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -883,6 +883,7 @@ extern int vfs_setlease(struct file *, long, struct file_lock **); extern int lease_modify(struct file_lock **, int); extern int lock_may_read(struct inode *, loff_t start, unsigned long count); extern int lock_may_write(struct inode *, loff_t start, unsigned long count); +extern struct seq_operations locks_seq_operations; struct fasync_struct { int magic; @@ -1375,12 +1376,25 @@ extern int locks_mandatory_area(int, struct inode *, struct file *, loff_t, size * Candidates for mandatory locking have the setgid bit set * but no group execute bit - an otherwise meaningless combination. */ -#define MANDATORY_LOCK(inode) \ - (IS_MANDLOCK(inode) && ((inode)->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID) + +static inline int __mandatory_lock(struct inode *ino) +{ + return (ino->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID; +} + +/* + * ... and these candidates should be on MS_MANDLOCK mounted fs, + * otherwise these will be advisory locks + */ + +static inline int mandatory_lock(struct inode *ino) +{ + return IS_MANDLOCK(ino) && __mandatory_lock(ino); +} static inline int locks_verify_locked(struct inode *inode) { - if (MANDATORY_LOCK(inode)) + if (mandatory_lock(inode)) return locks_mandatory_locked(inode); return 0; } @@ -1391,7 +1405,7 @@ static inline int locks_verify_truncate(struct inode *inode, struct file *filp, loff_t size) { - if (inode->i_flock && MANDATORY_LOCK(inode)) + if (inode->i_flock && mandatory_lock(inode)) return locks_mandatory_area( FLOCK_VERIFY_WRITE, inode, filp, size < inode->i_size ? size : inode->i_size, |