From: Christoph Hellwig Date: Tue, 27 Mar 2012 14:34:47 +0000 (-0400) Subject: xfs: reduce ilock hold times in xfs_file_aio_write_checks X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=467f78992a0743e0e71729e4faa20b67b0f25289;p=linux-beck.git xfs: reduce ilock hold times in xfs_file_aio_write_checks We do not need the ilock for generic_write_checks and the i_size_read, which are protected by i_mutex and/or iolock, so reduce the ilock critical section to just the call to xfs_zero_eof. Signed-off-by: Christoph Hellwig Reviewed-by: Dave Chinner Reviewed-by: Mark Tinguely Signed-off-by: Ben Myers --- diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 54a67dd9ac0a..3537c8d0af48 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -593,35 +593,31 @@ xfs_file_aio_write_checks( struct xfs_inode *ip = XFS_I(inode); int error = 0; - xfs_rw_ilock(ip, XFS_ILOCK_EXCL); restart: error = generic_write_checks(file, pos, count, S_ISBLK(inode->i_mode)); - if (error) { - xfs_rw_iunlock(ip, XFS_ILOCK_EXCL); + if (error) return error; - } /* * If the offset is beyond the size of the file, we need to zero any * blocks that fall between the existing EOF and the start of this * write. If zeroing is needed and we are currently holding the - * iolock shared, we need to update it to exclusive which involves - * dropping all locks and relocking to maintain correct locking order. - * If we do this, restart the function to ensure all checks and values - * are still valid. + * iolock shared, we need to update it to exclusive which implies + * having to redo all checks before. */ if (*pos > i_size_read(inode)) { if (*iolock == XFS_IOLOCK_SHARED) { - xfs_rw_iunlock(ip, XFS_ILOCK_EXCL | *iolock); + xfs_rw_iunlock(ip, *iolock); *iolock = XFS_IOLOCK_EXCL; - xfs_rw_ilock(ip, XFS_ILOCK_EXCL | *iolock); + xfs_rw_ilock(ip, *iolock); goto restart; } + xfs_rw_ilock(ip, XFS_ILOCK_EXCL); error = -xfs_zero_eof(ip, *pos, i_size_read(inode)); + xfs_rw_iunlock(ip, XFS_ILOCK_EXCL); + if (error) + return error; } - xfs_rw_iunlock(ip, XFS_ILOCK_EXCL); - if (error) - return error; /* * Updating the timestamps will grab the ilock again from @@ -638,7 +634,6 @@ restart: * people from modifying setuid and setgid binaries. */ return file_remove_suid(file); - } /*