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| author | Jonathan Corbet <corbet@lwn.net> | 2009-02-06 15:25:24 -0700 |
|---|---|---|
| committer | Jonathan Corbet <corbet@lwn.net> | 2009-03-16 08:32:27 -0600 |
| commit | db1dd4d376134eba0e08af523b61cc566a4ea1cd (patch) | |
| tree | 8882c673abbaa5713511b7046493fa862b9140d1 /fs | |
| parent | 684999149002dd046269666a390458e0acb38280 (diff) | |
| download | op-kernel-dev-db1dd4d376134eba0e08af523b61cc566a4ea1cd.zip op-kernel-dev-db1dd4d376134eba0e08af523b61cc566a4ea1cd.tar.gz | |
Use f_lock to protect f_flags
Traditionally, changes to struct file->f_flags have been done under BKL
protection, or with no protection at all. This patch causes all f_flags
changes after file open/creation time to be done under protection of
f_lock. This allows the removal of some BKL usage and fixes a number of
longstanding (if microscopic) races.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/fcntl.c | 2 | ||||
| -rw-r--r-- | fs/ioctl.c | 7 | ||||
| -rw-r--r-- | fs/nfsd/vfs.c | 5 |
3 files changed, 10 insertions, 4 deletions
@@ -189,7 +189,9 @@ static int setfl(int fd, struct file * filp, unsigned long arg) } } + spin_lock(&filp->f_lock); filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK); + spin_unlock(&filp->f_lock); out: unlock_kernel(); return error; @@ -404,10 +404,12 @@ static int ioctl_fionbio(struct file *filp, int __user *argp) if (O_NONBLOCK != O_NDELAY) flag |= O_NDELAY; #endif + spin_lock(&filp->f_lock); if (on) filp->f_flags |= flag; else filp->f_flags &= ~flag; + spin_unlock(&filp->f_lock); return error; } @@ -432,10 +434,12 @@ static int ioctl_fioasync(unsigned int fd, struct file *filp, if (error) return error; + spin_lock(&filp->f_lock); if (on) filp->f_flags |= FASYNC; else filp->f_flags &= ~FASYNC; + spin_unlock(&filp->f_lock); return error; } @@ -499,10 +503,7 @@ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd, break; case FIONBIO: - /* BKL needed to avoid races tweaking f_flags */ - lock_kernel(); error = ioctl_fionbio(filp, argp); - unlock_kernel(); break; case FIOASYNC: diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 6e50aaa..c165a64 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -998,8 +998,11 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, if (!EX_ISSYNC(exp)) stable = 0; - if (stable && !EX_WGATHER(exp)) + if (stable && !EX_WGATHER(exp)) { + spin_lock(&file->f_lock); file->f_flags |= O_SYNC; + spin_unlock(&file->f_lock); + } /* Write the data. */ oldfs = get_fs(); set_fs(KERNEL_DS); |
