# git rev-parse -q --verify 03275585cabd0240944f19f33d7584a1b099a3a8^{commit} 03275585cabd0240944f19f33d7584a1b099a3a8 already have revision, skipping fetch # git checkout -q -f -B kisskb 03275585cabd0240944f19f33d7584a1b099a3a8 # git clean -qxdf # < git log -1 # commit 03275585cabd0240944f19f33d7584a1b099a3a8 # Author: David Howells # Date: Tue Jul 4 20:22:15 2023 +0100 # # afs: Fix accidental truncation when storing data # # When an AFS FS.StoreData RPC call is made, amongst other things it is # given the resultant file size to be. On the server, this is processed # by truncating the file to new size and then writing the data. # # Now, kafs has a lock (vnode->io_lock) that serves to serialise # operations against a specific vnode (ie. inode), but the parameters for # the op are set before the lock is taken. This allows two writebacks # (say sync and kswapd) to race - and if writes are ongoing the writeback # for a later write could occur before the writeback for an earlier one if # the latter gets interrupted. # # Note that afs_writepages() cannot take i_mutex and only takes a shared # lock on vnode->validate_lock. # # Also note that the server does the truncation and the write inside a # lock, so there's no problem at that end. # # Fix this by moving the calculation for the proposed new i_size inside # the vnode->io_lock. Also reset the iterator (which we might have read # from) and update the mtime setting there. # # Fixes: bd80d8a80e12 ("afs: Use ITER_XARRAY for writing") # Reported-by: Marc Dionne # Signed-off-by: David Howells # Reviewed-by: Jeffrey Altman # Reviewed-by: Marc Dionne # cc: linux-afs@lists.infradead.org # cc: linux-fsdevel@vger.kernel.org # Link: https://lore.kernel.org/r/3526895.1687960024@warthog.procyon.org.uk/ # Signed-off-by: Linus Torvalds # < /opt/cross/kisskb/korg/gcc-8.5.0-nolibc/mips-linux/bin/mips-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-8.5.0-nolibc/mips-linux/bin/mips-linux-ld --version # < git log --format=%s --max-count=1 03275585cabd0240944f19f33d7584a1b099a3a8 # make -s -j 40 ARCH=mips O=/kisskb/build/linus_32r1el_defconfig_mips-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.5.0-nolibc/mips-linux/bin/mips-linux- 32r1el_defconfig Using /kisskb/src/arch/mips/configs/generic_defconfig as base Merging /kisskb/src/arch/mips/configs/generic/32r1.config Merging /kisskb/src/arch/mips/configs/generic/el.config Merging /kisskb/src/arch/mips/configs/generic/board-boston.config Merging /kisskb/src/arch/mips/configs/generic/board-marduk.config Merging /kisskb/src/arch/mips/configs/generic/board-ranchu.config Merging /kisskb/src/arch/mips/configs/generic/board-sead-3.config Merging /kisskb/src/arch/mips/configs/generic/board-virt.config # < make -s -j 40 ARCH=mips O=/kisskb/build/linus_32r1el_defconfig_mips-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.5.0-nolibc/mips-linux/bin/mips-linux- help # make -s -j 40 ARCH=mips O=/kisskb/build/linus_32r1el_defconfig_mips-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.5.0-nolibc/mips-linux/bin/mips-linux- olddefconfig # make -s -j 40 ARCH=mips O=/kisskb/build/linus_32r1el_defconfig_mips-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.5.0-nolibc/mips-linux/bin/mips-linux- Completed OK # rm -rf /kisskb/build/linus_32r1el_defconfig_mips-gcc8 # Build took: 0:01:01.169194