BKL: Explicitly add BKL around get_sb/fill_super
This patch is a preparation necessary to remove the BKL from do_new_mount(). It explicitly adds calls to lock_kernel()/unlock_kernel() around get_sb/fill_super operations for filesystems that still uses the BKL. I've read through all the code formerly covered by the BKL inside do_kern_mount() and have satisfied myself that it doesn't need the BKL any more. do_kern_mount() is already called without the BKL when mounting the rootfs and in nfsctl. do_kern_mount() calls vfs_kern_mount(), which is called from various places without BKL: simple_pin_fs(), nfs_do_clone_mount() through nfs_follow_mountpoint(), afs_mntpt_do_automount() through afs_mntpt_follow_link(). Both later functions are actually the filesystems follow_link inode operation. vfs_kern_mount() is calling the specified get_sb function and lets the filesystem do its job by calling the given fill_super function. Therefore I think it is safe to push down the BKL from the VFS to the low-level filesystems get_sb/fill_super operation. [arnd: do not add the BKL to those file systems that already don't use it elsewhere] Signed-off-by: Jan Blunck <jblunck@infradead.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Christoph Hellwig <hch@infradead.org>
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committed by
Arnd Bergmann

parent
899611ee7d
commit
db71922217
@@ -234,9 +234,13 @@ static int qnx4_fill_super(struct super_block *s, void *data, int silent)
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struct qnx4_sb_info *qs;
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int ret = -EINVAL;
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lock_kernel();
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qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
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if (!qs)
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if (!qs) {
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unlock_kernel();
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return -ENOMEM;
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}
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s->s_fs_info = qs;
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sb_set_blocksize(s, QNX4_BLOCK_SIZE);
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@@ -284,6 +288,7 @@ static int qnx4_fill_super(struct super_block *s, void *data, int silent)
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brelse(bh);
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unlock_kernel();
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return 0;
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outi:
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@@ -293,6 +298,7 @@ static int qnx4_fill_super(struct super_block *s, void *data, int silent)
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outnobh:
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kfree(qs);
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s->s_fs_info = NULL;
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unlock_kernel();
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return ret;
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}
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