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Use f_lock to protect f_flags

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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>
This commit is contained in:
Jonathan Corbet
2009-02-06 15:25:24 -07:00
parent 6849991490
commit db1dd4d376
13 changed files with 33 additions and 9 deletions
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7
drivers/usb/gadget/file_storage.c
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@@ -1711,7 +1711,9 @@ static int do_write(struct fsg_dev *fsg)
curlun->sense_data = SS_WRITE_PROTECTED;
return -EINVAL;
}
spin_lock(&curlun->filp->f_lock);
curlun->filp->f_flags &= ~O_SYNC; // Default is not to wait
spin_unlock(&curlun->filp->f_lock);
/* Get the starting Logical Block Address and check that it's
* not too big */
@@ -1728,8 +1730,11 @@ static int do_write(struct fsg_dev *fsg)
curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
return -EINVAL;
}
if (fsg->cmnd[1] & 0x08) // FUA
if (fsg->cmnd[1] & 0x08) { // FUA
spin_lock(&curlun->filp->f_lock);
curlun->filp->f_flags |= O_SYNC;
spin_unlock(&curlun->filp->f_lock);
}
}
if (lba >= curlun->num_sectors) {
curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;