The following functions in the fs/dcache.c file are changed to use the blocking reader seqlock as none of the dentries are being changed by those functions. This will allow other non-blocking readers to proceed when the blocking readers have taken the lock.
1. __d_path 2. d_absolute_path 3. d_path 4. dentry_path_raw 5. dentry_path 6. getcwd syscall Signed-off-by: Waiman Long <[email protected]> --- fs/dcache.c | 26 +++++++++++++------------- 1 files changed, 13 insertions(+), 13 deletions(-) diff --git a/fs/dcache.c b/fs/dcache.c index f09b908..480c81f 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -2603,9 +2603,9 @@ char *__d_path(const struct path *path, prepend(&res, &buflen, "\0", 1); br_read_lock(&vfsmount_lock); - write_seqlock(&rename_lock); + read_seqlock(&rename_lock); error = prepend_path(path, root, &res, &buflen); - write_sequnlock(&rename_lock); + read_sequnlock(&rename_lock); br_read_unlock(&vfsmount_lock); if (error < 0) @@ -2624,9 +2624,9 @@ char *d_absolute_path(const struct path *path, prepend(&res, &buflen, "\0", 1); br_read_lock(&vfsmount_lock); - write_seqlock(&rename_lock); + read_seqlock(&rename_lock); error = prepend_path(path, &root, &res, &buflen); - write_sequnlock(&rename_lock); + read_sequnlock(&rename_lock); br_read_unlock(&vfsmount_lock); if (error > 1) @@ -2692,9 +2692,9 @@ char *d_path(const struct path *path, char *buf, int buflen) get_fs_root(current->fs, &root); br_read_lock(&vfsmount_lock); - write_seqlock(&rename_lock); + read_seqlock(&rename_lock); error = path_with_deleted(path, &root, &res, &buflen); - write_sequnlock(&rename_lock); + read_sequnlock(&rename_lock); br_read_unlock(&vfsmount_lock); if (error < 0) res = ERR_PTR(error); @@ -2762,9 +2762,9 @@ char *dentry_path_raw(struct dentry *dentry, char *buf, int buflen) { char *retval; - write_seqlock(&rename_lock); + read_seqlock(&rename_lock); retval = __dentry_path(dentry, buf, buflen); - write_sequnlock(&rename_lock); + read_sequnlock(&rename_lock); return retval; } @@ -2775,7 +2775,7 @@ char *dentry_path(struct dentry *dentry, char *buf, int buflen) char *p = NULL; char *retval; - write_seqlock(&rename_lock); + read_seqlock(&rename_lock); if (d_unlinked(dentry)) { p = buf + buflen; if (prepend(&p, &buflen, "//deleted", 10) != 0) @@ -2783,7 +2783,7 @@ char *dentry_path(struct dentry *dentry, char *buf, int buflen) buflen++; } retval = __dentry_path(dentry, buf, buflen); - write_sequnlock(&rename_lock); + read_sequnlock(&rename_lock); if (!IS_ERR(retval) && p) *p = '/'; /* restore '/' overriden with '\0' */ return retval; @@ -2822,7 +2822,7 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) error = -ENOENT; br_read_lock(&vfsmount_lock); - write_seqlock(&rename_lock); + read_seqlock(&rename_lock); if (!d_unlinked(pwd.dentry)) { unsigned long len; char *cwd = page + PAGE_SIZE; @@ -2830,7 +2830,7 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) prepend(&cwd, &buflen, "\0", 1); error = prepend_path(&pwd, &root, &cwd, &buflen); - write_sequnlock(&rename_lock); + read_sequnlock(&rename_lock); br_read_unlock(&vfsmount_lock); if (error < 0) @@ -2851,7 +2851,7 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) error = -EFAULT; } } else { - write_sequnlock(&rename_lock); + read_sequnlock(&rename_lock); br_read_unlock(&vfsmount_lock); } -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
