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authorArnd Bergmann <arnd@arndb.de>2010-09-12 21:05:56 +0400
committerArnd Bergmann <arnd@arndb.de>2010-10-04 23:10:45 +0400
commit4f819a7899b06afcd7623ab9d00fd81503ad3e24 (patch)
tree4506a992e9207f6374803e89d9a0e9b9a9b33ddb /fs/isofs/isofs.h
parent3768744cfea7b995dce27f02341161fbfdfee80c (diff)
downloadlinux-4f819a7899b06afcd7623ab9d00fd81503ad3e24.tar.xz
BKL: Remove BKL from isofs
As in other file systems, we can replace the big kernel lock with a private mutex in isofs. This means we can now access multiple file systems concurrently, but it also means that we serialize readdir and lookup across sleeping operations which previously released the big kernel lock. This should not matter though, as these operations are in practice serialized through the hardware access. The isofs_get_blocks functions now does not take any lock any more, it used to recursively get the BKL. After looking at the code for hours, I convinced myself that it was never needed here anyway, because it only reads constant fields of the inode and writes to a buffer head array that is at this time only visible to the caller. The get_sb and fill_super operations do not need the locking at all because they operate on a file system that is either about to be created or to be destroyed but in either case is not visible to other threads. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'fs/isofs/isofs.h')
-rw-r--r--fs/isofs/isofs.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/isofs/isofs.h b/fs/isofs/isofs.h
index 7d33de84f52a..2882dc089f87 100644
--- a/fs/isofs/isofs.h
+++ b/fs/isofs/isofs.h
@@ -55,6 +55,7 @@ struct isofs_sb_info {
gid_t s_gid;
uid_t s_uid;
struct nls_table *s_nls_iocharset; /* Native language support table */
+ struct mutex s_mutex; /* replaces BKL, please remove if possible */
};
#define ISOFS_INVALID_MODE ((mode_t) -1)